JavaScript - Replace All Instances Within Page

I am using this script that gets messed up when you resize the window. I figured out that I could use this other script to do stuff just after the window gets resized.

Code:

(function($,sr){
 
  // debouncing function from John Hann
  // http://unscriptable.com/index.php/2009/03/20/debouncing-javascript-methods/
  var debounce = function (func, threshold, execAsap) {
      var timeout;
 
      return function debounced () {
          var obj = this, args = arguments;
          function delayed () {
              if (!execAsap)
                  func.apply(obj, args);
              timeout = null; 
          };
 
          if (timeout)
              clearTimeout(timeout);
          else if (execAsap)
              func.apply(obj, args);
 
          timeout = setTimeout(delayed, threshold || 100); 
      };
  }
	// smartresize 
	jQuery.fn[sr] = function(fn){  return fn ? this.bind('resize', debounce(fn)) : this.trigger(sr); };
 
})(jQuery,'smartresize');
 
 
// usage:
$(window).smartresize(function(){  
  // code that takes it easy...
});

So I re-instantiate the misbehaving script in there so it fires whenever the window is resized (I changed it to 500 so it really only fires once after you are done resizing). This fixes it. The new instance doesn't have a problem but the old instance is still there and messed up. so I use. $($.misbehaving-script).remove(); just before instantiating after window resize, which gets rid of broken instance.

Problem solved.. Except that messes up a different script! It's driving me crazy.

Any advice would of course be very welcome.

Hi I need help with spawning in my game.

I have this code:

Code:

function spawnEnemy()
{
    var shapes = [LeftBlock, RightBlock, middleRightBlock, middleLeftBlock, middleBlock];
    var shape = shapes[Math.floor(Math.random() * shapes.length)];
    var RandomBlock = new THREE.Object3D();
    RandomBlock.add(shape);
    blocks.push(RandomBlock);

     for (var i = 0; i < blocks.length; i++) {
        RandomBlock = blocks[i];
        scene.add(RandomBlock);
        hit = false; 
        
     }

}


function startSpawningEnemies()
{

  repeater = setInterval(function() {
      spawnEnemy();
      newBlock = false;
  }, 1000);


}

Basically it chooses a random object in the array 'shapes' and it adds the shape to the scene every second.

But the problem is that when I have, for example a 'Leftblock' on screen and it randomly gets called again, Leftblock will get reset to the starting position, so basically I cant have 2 of the same type of block on screen at once.

So I want want every block in the array to be an entirely new instance of a block, rather than the same.

Here is a code pen so you can see what is happening My Codepen

Thanks in advance





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01-31-2015, 12:06 PM #2
Lesshardtofind View Profile View Forum Posts Visit Homepage

New Coder Join Date Sep 2013 Location Houston Posts 20 Thanks 0 Thanked 4 Times in 4 Posts

Hey I apologize in advance this will probably be a long post, but to get to the root of your problem it takes a bit of explaining to show how I fixed it. If you don't want to read about all the changes and why I did them if you scroll to the bottom of this post the last code snippet is the new working code.

Firstly I'd like to make a few comments.
1. Try to avoid using so many globals that is what is confusing the whole thing.
2. Even though JavaScript isn't a classical language. Using some OOP approaches can simplify your code quite a bit.

Now to what your actual problem was. You only had one instance of meshes for each type of block/paddle or whatever you call it. Even though you created new 3d objects you still were just passing it the values of the current existing Meshes.

In order to get around this I simplified your code a lot. I removed around 200 lines of code and created a few objects to make things easier. I don't know that I can explain every single thing I did, but creating objects is very useful for instance instead of making a ton of variables for each box you can make an Object called Box and then create a new instance of it. Since your Box also needs a mesh you can create that inside of the box as well.

Code:

function Box(w, h, d, q, m){
    var CoreInfo = {
        width: w,
        height: h,
        depth: d,
        quality: q,
        material: m
    };
    var Mesh = GetNewMesh(CoreInfo);
    this.setMeshY = function(y){
        Mesh.position.y = y;
    }
    this.setMeshX = function(x){
        Mesh.position.x = x;
    }
    this.getCoreInfo = function(key){
        return CoreInfo[key];
    }
    this.setCoreInfo = function(key, val){
        CoreInfo[key] = val;
    }
    this.getAllInfo = function(){
        return CoreInfo;
    }
    this.getMesh = function(){
        return Mesh;
    }
    this.setShadows = function(r, c){
        Mesh.receiveShadow = r;
        Mesh.castShadow = c;
    }
}
// you will notice that it calls this to get a MESH instead of using 5+ serperate calls you can now wrap it into a function that takes an assoc array.
function GetNewMesh(info){
    var Q = info["qaulity"];
    return new THREE.Mesh(
        new THREE.BoxGeometry(
            info["width"],
            info["height"],
            info["depth"],
            Q, Q, Q),
        info["material"]);
}

With this object you can create new instances of boxes just by passing all the variables it needs and save it into a new object.
example use:

Code:

var BlockMat = new THREE.MeshLambertMaterial({color: 0x3c00ff});
var Abox = new Box(10, 160, 10, 1, BlockMat);

As you can see the Box requires 5 arguments to construct. They are width, height, depth, quality, and material;
You will also notice there are functions inside of the Box to call functionality they are
setMeshY(y): This sets the Y position of the mesh as the y value passed to it;
setMeshX(x): This sets the X position of the mesh as the x value passed to it;
getCoreInfo(key): This gets some CoreInfo based on a string or "key" that you pass it. EX use Box.getCoreInfo("width");
setCoreInfo(key, value): This sets some CoreInfo based on a string or "key" that you pass it. EX use Box.setCoreInfo("width", 100);
getAllInfo(): Returns ALL CoreInfo in an assoc array that is accessed by a "key." EX use var AllInfo = Box.getAllInfo(); AllInfo["width"];
getMesh: Returns The mesh object
setShadows: Allows you to set shadows by passing true or false for the receive and cast arguments.

Now some of your enemy boxes needed two boxes so I further created a object called Double Box;

These are very much the same as a box. Just all methods need to be passed an index as well. These are identical to your original objects as Paddle1 is now at index 0, and Paddle2 is at index1 for each respective object.

With those objects created we can Delete a TON of your global variables and clean some stuff up. As a matter of fact the more I looked at it you didn't even NEED globals for your set enemy paddle types at all. I was able to wrap them all up into a function that will return an object like you wanted by being passed a string.

Code:

function GetBlock(type){
    if(type == "m"){
        var temp = new DoubleBox(10, 75, 10, 1, BlockMat, 10, 75, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh(0));
        obj.add(temp.getMesh(1))
        temp.setMeshX(0, fieldWidth/2);
        temp.setMeshY(0, -60);
        temp.setMeshX(1, fieldWidth/2);
        temp.setMeshY(1, 60);
        return obj;
    }
    else if(type == "mr"){
        var temp = new DoubleBox(10, 30, 10, 1,BlockMat, 10, 110, 10, 1,BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh(0));
        obj.add(temp.getMesh(1));
        temp.setMeshX(0, fieldWidth/2);
        temp.setMeshY(0, -80);
        temp.setMeshX(1, fieldWidth/2);
        temp.setMeshY(1, 40);
        return obj;
    }
    else if(type == "ml"){
        var temp = new DoubleBox(10, 30, 10, 1, BlockMat, 10, 110, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh(0));
        obj.add(temp.getMesh(1));
        temp.setMeshX(0, fieldWidth/2);
        temp.setMeshY(0, 80);
        temp.setMeshX(1, fieldWidth/2);
        temp.setMeshY(1, -40);
        return obj;
    }
    else if(type == "l"){
        var temp = new Box(10, 160, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh());
        temp.setMeshX(fieldWidth/2);
        temp.setMeshY(20);
        return obj;
    }
    else if(type == "r"){
        var temp = new Box(10, 160, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh());
        temp.setMeshX(fieldWidth/2);
        temp.setMeshY(-20);
        return obj;
    }
}

While this could be cleaned up and do some extra error checking it now does EXACTLY what you need it to. You can call this function and pass it a string for each type of block you want. It will return a NEW instance of that type of block without sharing meshes as you had previously programmed it to.

now you can call this function in the spawn enemy function
Code:

function spawnEnemy() //total enemies starts at 0 and every-time you add to array
{
    var shapes = ["l", "r", "mr", "ml", "m"];  // these are the strings that pass to the GetBlock(type) function as type
    var shape = shapes[Math.floor(Math.random() * shapes.length)];
    blocks.push(new THREE.Object3D().add(GetBlock(shape))); // now you just pass the function to the THREE.Object3d().add() accepting shape as a parameter.

    for (var i = 0; i < blocks.length; i++) {
        RandomBlock = blocks[i];
        scene.add(RandomBlock);
        hit = false;
    }

}

I know I made a lot of changes and there are still plenty more that could reduce your code even further, but when I finally got to a point where it was working the way you wanted to I figured I'd hand it back over to you.

HERE is the final code that works if you want to copy paste it over to test it.

Code:

//scene object variables
var renderer, scene, camera, pointLight, spotLight;

var hit;
var newBlock = false;
//field variables
var fieldWidth = 500, fieldHeight = 200;

function GetNewMesh(info){
    var Q = info["qaulity"];
    return new THREE.Mesh(
        new THREE.BoxGeometry(
            info["width"],
            info["height"],
            info["depth"],
            Q, Q, Q),
        info["material"]);
}

function Box(w, h, d, q, m){
    var CoreInfo = {
        width: w,
        height: h,
        depth: d,
        quality: q,
        material: m
    };
    var Mesh = GetNewMesh(CoreInfo);
    this.setMeshY = function(y){
        Mesh.position.y = y;
    }
    this.setMeshX = function(x){
        Mesh.position.x = x;
    }
    this.getCoreInfo = function(key){
        return CoreInfo[key];
    }
    this.setCoreInfo = function(key, val){
        CoreInfo[key] = val;
    }
    this.getAllInfo = function(){
        return CoreInfo;
    }
    this.getMesh = function(){
        return Mesh;
    }
    this.setShadows = function(r, c){
        Mesh.receiveShadow = r;
        Mesh.castShadow = c;
    }
}

function DoubleBox(B1w, B1h, B1d, B1q, B1m, B2w, B2h, B2d, B2q, B2m) {
    var Boxes = [];
    Boxes[0] = new Box(B1w, B1h, B1d, B1q, B1m);
    Boxes[1] = new Box(B2w, B2h, B2d, B2q, B2m);
    this.setMeshY = function (index, y) {
        Boxes[index].setMeshY(y);
    }
    this.setMeshX = function (index, x) {
        Boxes[index].setMeshX(x);
    }
    this.getCoreInfo = function (index, key) {
        return Boxes[index].getCoreInfo(key);
    }
    this.setCoreInfo = function (index, key, val) {
        Boxes[index].setCoreInfo(key, val);
    }
    this.getAllInfo = function (index) {
        return Boxes[index].getAllInfo();
    }
    this.getMesh = function (index) {
        return Boxes[index].getMesh();
    }
    this.setShadows = function (index, r, c) {
        Boxes[index].setShadows(r, c);
    }
}

var BlockMat = new THREE.MeshLambertMaterial({color: 0x3c00ff});

var Player = new Box(10, 30, 10, 1, new THREE.MeshLambertMaterial({color: 0x4AA02C}));
function GetBlock(type){
    if(type == "m"){
        var temp = new DoubleBox(10, 75, 10, 1, BlockMat, 10, 75, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh(0));
        obj.add(temp.getMesh(1))
        temp.setMeshX(0, fieldWidth/2);
        temp.setMeshY(0, -60);
        temp.setMeshX(1, fieldWidth/2);
        temp.setMeshY(1, 60);
        return obj;
    }
    else if(type == "mr"){
        var temp = new DoubleBox(10, 30, 10, 1,BlockMat, 10, 110, 10, 1,BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh(0));
        obj.add(temp.getMesh(1));
        temp.setMeshX(0, fieldWidth/2);
        temp.setMeshY(0, -80);
        temp.setMeshX(1, fieldWidth/2);
        temp.setMeshY(1, 40);
        return obj;
    }
    else if(type == "ml"){
        var temp = new DoubleBox(10, 30, 10, 1, BlockMat, 10, 110, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh(0));
        obj.add(temp.getMesh(1));
        temp.setMeshX(0, fieldWidth/2);
        temp.setMeshY(0, 80);
        temp.setMeshX(1, fieldWidth/2);
        temp.setMeshY(1, -40);
        return obj;
    }
    else if(type == "l"){
        var temp = new Box(10, 160, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh());
        temp.setMeshX(fieldWidth/2);
        temp.setMeshY(20);
        return obj;
    }
    else if(type == "r"){
        var temp = new Box(10, 160, 10, 1, BlockMat);
        var obj = new THREE.Object3D();
        obj.add(temp.getMesh());
        temp.setMeshX(fieldWidth/2);
        temp.setMeshY(-20);
        return obj;
    }
}

//ball variables
var reftBlock, lightBlock, middleRightBlock, middleLeftBlock, middleBlock, RandomBlock;

//game-related variables
var score = 0;

var repeater;
var blocks = [];

var collidableMeshList = [];

function setup()
{
//	update the board to reflect the max score for match win
    document.getElementById("winnerBoard").innerHTML = "Move in the gaps!";

//	set up all the 3D objects in the scene
    createScene();

//	and let's get cracking!
    draw();
}

function createScene()
{
//	set the scene size
    var WIDTH = 640,
        HEIGHT = 360;

//	set some camera attributes
    var VIEW_ANGLE = 50,
        ASPECT = WIDTH / HEIGHT,
        NEAR = 0.1,
        FAR = 10000;

    var c = document.getElementById("gameCanvas");

//	create a WebGL renderer, camera
//	and a scene
    renderer = new THREE.WebGLRenderer({antialias:true});
    renderer.setClearColorHex(0xffffff);

    camera =
        new THREE.PerspectiveCamera(
            VIEW_ANGLE,
            ASPECT,
            NEAR,
            FAR);

    scene = new THREE.Scene();

//	add the camera to the scene
    scene.add(camera);

//	set a default position for the camera
//	not doing this somehow messes up shadow rendering
    //camera.position.z = 320;

//	start the renderer
    renderer.setSize(WIDTH, HEIGHT);

//	attach the render-supplied DOM element
    c.appendChild(renderer.domElement);

//	set up the playing surface plane
    var planeWidth = fieldWidth,
        planeHeight = fieldHeight,
        planeQuality = 10;

//	create the plane's material
    var planeMaterial =
        new THREE.MeshLambertMaterial(
            {
                color: 0xffffff
            });
//	create the table's material
    var tableMaterial =
        new THREE.MeshLambertMaterial(
            {
                color: 0x3c00ff
            });
//	create the ground's material
    var groundMaterial =
        new THREE.MeshLambertMaterial(
            {
                color: 0xffffff
            });


//	create the playing surface plane
    var plane = new THREE.Mesh(

        new THREE.PlaneGeometry(
            planeWidth * 1.25,	// 95% of table width, since we want to show where the ball goes out-of-bounds
            planeHeight,
            planeQuality,
            planeQuality),

        planeMaterial);

    scene.add(plane);
    plane.receiveShadow = true;

    var table = new THREE.Mesh(

        new THREE.BoxGeometry(
            planeWidth * 1.15,	// this creates the feel of a billiards table, with a lining
            planeHeight * 1.04,
            100,	// an arbitrary depth, the camera can't see much of it anyway
            planeQuality,
            planeQuality,
            1),

        tableMaterial);
    table.position.z = -51;	// we sink the table into the ground by 50 units. The extra 1 is so the plane can be seen
    scene.add(table);
    table.receiveShadow = true;

    scene.add(Player.getMesh());
    startSpawningEnemies();


    Player.setShadows(true, true)

    /*collidableMeshList.push(MiddleBlock.getMesh(0), MiddleBlock.getMesh(1),
        MiddleLeftBlock.getMesh(0), MiddleLeftBlock.getMesh(1), MiddleRightBlock.getMesh(0),
        MiddleRightBlock.getMesh(1), RightBlock.getMesh(), LeftBlock.getMesh());*/


//	set paddles on each side of the table
    Player.setMeshX(-fieldWidth/2 + Player.getCoreInfo("width"));

    //collidableMeshList.push(RandomBlock);

//	finally we finish by adding a ground plane
//	to show off pretty shadows
    var ground = new THREE.Mesh(

        new THREE.BoxGeometry(
            1000,
            1000,
            3,
            1,
            1,
            1 ),

        groundMaterial);
    // set ground to arbitrary z position to best show off shadowing
    ground.position.z = -132;
    ground.receiveShadow = true;
    scene.add(ground);

//	// create a point light
    pointLight =
        new THREE.PointLight(0xffffff);

//	set its position
    pointLight.position.x = -1000;
    pointLight.position.y = 0;
    pointLight.position.z = 1000;
    pointLight.intensity = 2.9;
    pointLight.distance = 10000;
//	add to the scene
    scene.add(pointLight);

//	add a spot light
//	this is important for casting shadows
    spotLight = new THREE.SpotLight(0xffffff);
    spotLight.position.set(0, 0, 460);
    spotLight.intensity = 1.5;
    spotLight.castShadow = true;
    scene.add(spotLight);

//	MAGIC SHADOW CREATOR DELUXE EDITION with Lights PackTM DLC
    renderer.shadowMapEnabled = true;


}

function draw()
{
//	draw THREE.JS scene
    renderer.render(scene, camera);
//	loop draw function call
    requestAnimationFrame(draw);

    cameraPhysics();
    playerPaddleMovement();
    enemyPaddleMovement();
    collision();
    //addScore();
}

function addScore()
{
   if (RandomBlock.position.x < Pad.getMesh().position.x*2 && newBlock == false) {
        console.log("pass");
        newBlock = true;
        if (hit == false) {
            score++;
        }
        else {
            score--
        }
        document.getElementById("scores").innerHTML = score;
    }
}

function enemyPaddleMovement()
{
    if(score < 10)
    {
        for (var i = 0; i < blocks.length; i++) {

            blocks[i].position.x -= 3;
        }
    }

    if(score >= 10)
    {
        for (var i = 0; i < blocks.length; i++) {

            blocks[i].position.x -= 5;
        }

    }

}


function playerPaddleMovement()
{
    if (Key.isDown(Key.D))
        Player.setMeshY(80);
    else if (Key.isDown(Key.F))
        Player.setMeshY(40);
    else if (Key.isDown(Key.H))
        Player.setMeshY(0);
    else if (Key.isDown(Key.J))
        Player.setMeshY(-40);
    else if (Key.isDown(Key.K))
        Player.setMeshY(-80);
}

//Handles camera and lighting logic
function cameraPhysics()
{

//	move to behind the player's paddle
    camera.position.x = Player.getMesh().position.x - 100;
    camera.position.y += (Player.getMesh().position.y - camera.position.y) * 0.05;
    camera.position.z = Player.getMesh().position.z + 100 + 0.04 * (Player.getMesh().position.x);

//	rotate to face towards the opponent
    camera.rotation.y = -60 * Math.PI/180;
    camera.rotation.z = -90 * Math.PI/180;
}

//Handles paddle collision logic
function collision()
{
    var originPoint = Player.getMesh().position.clone();

    for (var vertexIndex = 0; vertexIndex < Player.getMesh().geometry.vertices.length; vertexIndex++)
    {

        var ray = new THREE.Raycaster( originPoint, Player.getMesh().geometry.vertices[vertexIndex] );
        var collisionResults = ray.intersectObjects( collidableMeshList );
        if ( collisionResults.length > 0)
        {
            console.log("true");
            hit = true;
        }
    }
}


function resetBall()
{

}

//checks if either player or opponent has reached 7 points
function matchScoreCheck()
{

}

function spawnEnemy() //total enemies starts at 0 and every-time you add to array
{
    var shapes = ["l", "r", "mr", "ml", "m"];
    var shape = shapes[Math.floor(Math.random() * shapes.length)];
    blocks.push(new THREE.Object3D().add(GetBlock(shape)));

    for (var i = 0; i < blocks.length; i++) {
        RandomBlock = blocks[i];
        scene.add(RandomBlock);
        hit = false;
    }

}


function startSpawningEnemies()
{

    repeater = setInterval(function() {
        spawnEnemy();
        newBlock = false;
    }, 1000); //this calls spawnEnemy every spawnRate
    /////////spawn 'spawnAmount' enemies every 2 seconds

}

I also commented out your addScore() function because it references RandomBlock which is not defined in its scope and the error message was annoying for debugging. I also commented out the collision as you will need to think of a new method for doing that. Most likely just build a function that accepts an array and then just pass it your blocks array and let it loop through it.

Overall cool game good luck to ya. Don't hesitate to reach out if you have any other questions.





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Users who have thanked Lesshardtofind for this post: TeaAnyOne (01-31-2015)



01-31-2015, 02:31 PM #3
TeaAnyOne View Profile View Forum Posts

New to the CF scene Join Date Jan 2015 Posts 4 Thanks 2 Thanked 0 Times in 0 Posts

Wow! I didn't expect such a huge reply, it seems that my original code has changed a lot and I will have to give it a hard look through it to understand it.

I will contact you if I have any questions, I have a lot of work ahead of me.

Thanks a lot





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01-31-2015, 04:45 PM #4
TeaAnyOne View Profile View Forum Posts

New to the CF scene Join Date Jan 2015 Posts 4 Thanks 2 Thanked 0 Times in 0 Posts

I suppose I do have one more question.

How do I get the position.x of the Randomblocks. I tried using a for loop like this:

for (var i = 0; i < blocks.length; i++) {
if (blocks[i].position.x === Player.getMesh().position.x*2 && newBlock === false) {
console.log("pass");
newBlock = true;
if (hit === false) {
score++;
}
else {
score--;
}
}

document.getElementById("scores").innerHTML = score;
}
}

it works but it seems kind of buggy as it stops counting to 10 when it changes speed.

Is there another way to retrieve the position?





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01-31-2015, 07:43 PM #5
Lesshardtofind View Profile View Forum Posts Visit Homepage

New Coder Join Date Sep 2013 Location Houston Posts 20 Thanks 0 Thanked 4 Times in 4 Posts

That should work for getting the position since the Blocks are objects of type THREE.Object3d so any methods they have should work for you.

You may be having problems because you never despawn enemies ultimately getting a huge number of 3d objects in your array blocks, or you may find your position requirement doesn't mathematically work with your speed up.

Sometimes just using a few extra console.logs to track your numbers inside of functions that don't seem to be working can help you to get an idea of what values it is seeing for the numbers and when. It might make the problem super obvious. This more like shotgun debugging which is discouraged by many, but I found it to help a lot when I was first learning code. Ultimately you want to understand your logic in each function and how it can fail when you program it, and then use error checking to make sure no parameters get outside of your allowed variance.





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Users who have thanked Lesshardtofind for this post: TeaAnyOne (01-31-2015)



01-31-2015, 08:27 PM #6
TeaAnyOne View Profile View Forum Posts

New to the CF scene Join Date Jan 2015 Posts 4 Thanks 2 Thanked 0 Times in 0 Posts

OK ill see if I can get it working.

Thanks for all your help! It helped me a lot.





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01-31-2015, 08:31 PM #7
Old Pedant View Profile View Forum Posts

Supreme Master coder! Join Date Feb 2009 Posts 28,310 Thanks 82 Thanked 4,754 Times in 4,716 Posts


Originally Posted by Lesshardtofind
Ultimately you want to understand your logic in each function and how it can fail when you program it, and then use error checking to make sure no parameters get outside of your allowed variance.



Very well said!

Hi,

I have written a code below:

Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <script type="text/javascript">
            function emailRowContent(isSelected, emailAddress, severity)
            {
                var emailRowObj = document.getElementById('emailRow');
                
                emailRowObj.childNodes[1].childNodes[0].checked = isSelected;
                emailRowObj.childNodes[3].childNodes[0].value   = emailAddress;
                emailRowObj.childNodes[5].childNodes[0].checked = severity;
            }
            
            function LoadUp()
            {
                var emailAddressListObj = document.getElementById('emailAddressList');
                var arrayOfEmails = new Array(5);
                
                for (i = 0; i < 5; i++)
                {
                   arrayOfEmails[i] = new emailRowContent( "checked", "fjkum@unknown.com" + i, i );                                                       
                   //emailAddressListObj.appendChild( arrayOfEmails[i] ); /* Somehow this line breaks */                   
                }
            }
        </script>
        <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
        <title>Insert title here</title>
    </head>
    <body onload="javascript:LoadUp();">
        <div id="emailRow" class="emailRowClass">
            <div><input type="checkbox" class="checkbox1"></div>
            <div><input type="text" class="textfield"></div>
            <div><input type="checkbox" class="checkbox2"></div>
        </div>
        
        <div id="emailAddressList" class="emailAddressClass"></div>
    </body>
</html>

Basically, what I want to do is to dynamically create 5 instances of "emailRow" onto the web page making use of Javascript DOM. But have no success in getting it to work.

Can anyone shed some light?

Mike

Hi,

I have a question about an oop/class style form of javascript programming.

I have stripped the code down to the basic minimum. The problem is I have created two instances of the same class and have entered data into those classes. But as you will see the two separate instances of the class appear to share the same data.

How do I get my class structure working so separate instances will retain their separate data?

Here is the code:

Index.html
Code:

<html>
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8">
<script type="text/javascript" src="test.js"></script>
<script type="text/javascript">
debugger;

// Do this because a page resart seems to keep old data
function SetGlobals()
{
	var ui;
	var el;
	
	// Arr00
	ui = document.getElementById("Arr00");
	el = arr0.arrayGet(0);
	ui.innerHTML = el.m_String;
	
	// Arr01
	ui = document.getElementById("Arr01");
	el = arr0.arrayGet(1);
	ui.innerHTML = el.m_String;
	
	// Arr10
	ui = document.getElementById("Arr10");
	el = arr1.arrayGet(0);
	ui.innerHTML = el.m_String;
	
	// Arr11
	ui = document.getElementById("Arr11");
	el = arr1.arrayGet(1);
	ui.innerHTML = el.m_String;
}

function MyOnLoad()
{
	SetGlobals();
}
</script>
</head>
<body onload="MyOnLoad()" style="width:100%; height: 100%; padding: 0 0 0 0; margin: 0 0 0 0; overflow: hidden; background:#000000">

<div id="divScreen" style="display: block; width:100%; height="100%">
	<div id="divMenu" style='float: left; background:#00FF00; border-color: #000000; border-width: 1px;'>
		<table>
			<tr>
				<td>
					Array 0/String 0: <label id="Arr00"></label>
				</td>
			</tr>
			<tr>
				<td>
					Array 0/String 1: <label id="Arr01"></label>
				</td>
			</tr>
			<tr>
				<td>
					Array 1/String 0: <label id="Arr10"></label>
				</td>
			</tr>
			<tr>
				<td>
					Array 1/String 1: <label id="Arr11"></label>
				</td>
			</tr>
		</table>
	</div>
	<div id="divMain" style='height: 100%; background:#0000FF; margin-left: 250px; border-color: #000000; border-width: 1px;'>
	</div>
</div>
</body>
</html>

Test.js
Code:

var BaseARR = function()
{
	_arr = []; // new Array();
		
	// Public functions that can access private members
	this.Add = function(arg)
	{
        var i, addAt;
 
		if(arg==null || (addAt = FindEnterPos(arg))<0)
		    return false;
				
		// since adding and not deleting anything, nothing of value will be returned
		_arr.splice(addAt, 0, arg);

        return true;
	};
	// This finds the entry position for in
    FindEnterPos = function(arg)
    {
		return (_arr.length + 1);
    };
	this.arrayGet = function(i)
	{
		return ((_arr != null && i >= 0 && i < _arr.length) ? _arr[i] : null);
	};
};

var stringId = function(id, str)
{
	// public has a this. , privates have just var
	this.m_Id = id; // int
	this.m_String = str; // string
};

// This so allow statics
var stringIdARR = function()
{
	BaseARR.call(this);
};

I'm working on code for my forums that will allow users to post text which can be moused over to display an image that will follow the cursor (provided the cursor is hovering above the specific text).

The code works, but it obviously can't be used for more than one picture per page because getElementById finds the first div and always displays it onmouseover of any attempted mouseover text.

The Javascript in <head> is
Code:

<script type="text/javascript">

// Pop up code begin

function ShowPopup(hoveritem)
{
hp = document.getElementById("hoverpopup");

// Set popup to visible
hp.style.visibility = "Visible";
}

function HidePopup()
{
hp = document.getElementById("hoverpopup");
hp.style.visibility = "Hidden";
}

// Follow mouse script begin

var divName = 'hoverpopup'; // div that is to follow the mouse
                       // (must be position:absolute)
var offX = 5;          // X offset from mouse position
var offY = 5;          // Y offset from mouse position

function mouseX(evt) {if (!evt) evt = window.event; if (evt.pageX) return evt.pageX; else if (evt.clientX)return evt.clientX + (document.documentElement.scrollLeft ?  document.documentElement.scrollLeft : document.body.scrollLeft); else return 0;}
function mouseY(evt) {if (!evt) evt = window.event; if (evt.pageY) return evt.pageY; else if (evt.clientY)return evt.clientY + (document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop); else return 0;}

function follow(evt) {if (document.getElementById) {var obj = document.getElementById(divName).style;
obj.left = (parseInt(mouseX(evt))+offX) + 'px';
obj.top = (parseInt(mouseY(evt))+offY) + 'px';}}
document.onmousemove = follow;
</script>

So the display code is
Code:

<a id="hoverover" style="cursor:default;" onMouseOver="ShowPopup(this);" onMouseOut="HidePopup();">text here</a>
<div id="hoverpopup" style="visibility:hidden; position:absolute;"><img src="url here"></div>

I just want to be able to have more than one instance on each page and still be able to declare the image url in the body and not within the javascript.

I'm pretty new to Javascript and just started with some OOP concepts, so this might be an obvious one and I apologize if the question is much longer than it should be...

Basically I am trying to create a reusable class object with several internal functions, that is completely abstracted, meaning the class object itself should never have to reference the global declarations or window object. This class should be aware of itself at any point in the execution of it's own functions, and that is what I'm having trouble with at the moment.

What I'm trying to do is create reusable javascript "Apps" for my HTML web application, where multiple instances can be instantiated and used independently from one another.

My main problem is "this" loses context in the Ajax callback and onclick handlers. I'm not sure how to persist the context of "this", or at least keep a reference to prototype instance itself.

Let's set up a simple class called "App" to demonstrate what I mean...

Code:

var myApp = new App("MyFirstApp");

function App(argName) {
    this.name = argName;
    this.GetDirectory("C:\Program Files");
}

App.prototype.GetDirectory = function(argPath) {
    // "this" equals the App object instance (good!), meaning this.name should equal "MyFirstApp"
    Ajax.GetDirectory(argPath, this.GetDirectoryCallback, this.GetDirectoryTimeout, this.GetDirectoryError);
}

App.prototype.GetDirectoryCallback = function(argFilePaths) {
    // "this" equals the "window" object (bad!), meaning this.name should equal a null reference
    // argFilePaths contains a string of file paths (delimited using ;) returned by the server
    var mFilePaths = split(argFilePaths, ";");
    // for each file path, add a div to the document body containing that file path, with an onclick handler
    for (var i in mFilePaths) {
        var mFilePath = mFilePaths[i];
        var mFilePathDiv = document.createElement("div");
        mFilePathDiv.innerHTML = mFilePath;
        mFilePathDiv.setAttribute("onclick", "javascript:this.FilePathDivClickHandler();return false;");
        document.getElementById("body").appendChild(mFilePathDiv);
    }
}

App.prototype.FilePathDivClickHandler = function() {
    // I need a reference to the App object instance here, but I'm not sure where to grab it...
    // what I want to do is call GetDirectory again, referencing the div's innerHTML which contains another file path, like this:
    this.GetDirectory(event.target.innerHTML);
}

The onclick handler using "this" is obviously not going to work because "this" is a reference to the "window" object which does not have a function called FilePathDivClickHandler(). So what I can do is nest the GetDirectoryCallback() function inside the GetDirectory() function so that GetDirectoryCallback() can reference the variables in the outer function (GetDirectory).

Code:

App.prototype.GetDirectory = function(argPath) {
    // "this" equals the App object instance (good!), meaning this.name should equal "MyFirstApp"
    // "this" will still lose context inside the callback, so we can set up a variable called "instance" that the callback can reference
    var instance = this;
    Ajax.GetDirectory(argPath, GetDirectoryCallback, GetDirectoryTimeout, GetDirectoryError);
    function GetDirectoryCallback(argFilePaths) {
        // "this" equals the window object (bad!), meaning this.name should equal a null reference
        // "instance" equals the App object instance (good!), meaning instance.name should equal "MyFirstApp"
        // argFilePaths contains a string of file paths (delimited using ;) returned by the server
        var mFilePaths = split(argFilePaths, ";");
        // for each file path, add a div to the document body containing that file path, with an onclick handler
        for (var i in mFilePaths) {
            var mFilePath = mFilePaths[i];
            var mFilePathDiv = document.createElement("div");
            mFilePathDiv.innerHTML = mFilePath;
            mFilePathDiv.setAttribute("onclick", "javascript:instance.FilePathDivClickHandler();return false;");
            document.getElementById("body").appendChild(mFilePathDiv);
        }
    }
}

Even though we have persisted the App object instance through the use of the "instance" variable in the outer function, the onclick event handler still does not work; when it fires, "instance" is an unknown object.

Would placing the FilePathDivClickHandler() function inside the GetDirectory() function, much like what was done with the callback, allow me to use "instance" correctly for the onclick handler?

The statement does what I want it to do, except if there is multiple instances of the word, it only outputs one, how can I work it so all instances are output in red? (while still using .slice)

var phrase = prompt("Enter a messate: ", 'Message');
var searchFor = prompt("Enter search text: ", 's');
var matchPhrase = "";
var searchIndex = -1;

/* if there's a match, create a text string by
* add the phrase text from before the match,
* add <font> tags around the match text,
* add the rest of the phrase from after the match
*/
searchIndex = phrase.indexOf(searchFor);
if (searchIndex >=0 ) {
// Copy text from phrase up till the match.
matchPhrase += phrase.slice(0, searchIndex);
matchPhrase += '<font color="red">' + searchFor + '</font>';
matchPhrase += phrase.slice(searchIndex + searchFor.length);
phrase++

} else {
matchPhrase = "No matches"
}

document.writeln(matchPhrase);





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01-31-2015, 09:08 AM #2
Philip M View Profile View Forum Posts

Supreme Master coder! Join Date Jun 2002 Location London, England Posts 18,371 Thanks 204 Thanked 2,573 Times in 2,551 Posts

Use a regular expression.

i am trying to make an online graphing calculator with javascript. dont ask how because i dont know. but there is an annoying error in a do...while loop. although it should break out of the loop when the |'s (absolute value signs) are replaced with Math.abs( and ). here is the code.

Code:

var initec = function(){
    var rg = {
    }
    ;
    rg.matc = false;
    rg.i = 0;
    rg.change = function(equ){
        if (typeof(equ) != "string"){
            alert('Equation must be a string');
            return;
        }
         alert("starting equation: "+ equ);
        rg.i = 0;
        do{
            rg.matc = equ.match(/\|/);
            if(rg.i === 0){
                equ.replace(/\|/, " Math.abs(");
                rg.i = 1;
                alert("1 "+equ);
            }
            else {
                equ.replace(/\|/, " ) ");
                rg.i = 0;
                alert("0 "+equ);
            }
        }while(rg.matc) 
        alert("finished equation: " + equ);
    }
return rg;
}

rg=initec();
rg.change("|8/x+7|-2");

the last 2 lines and the alerts are for debugging. as you can see, it is not finished. but still, it should work.

Hi there,

I've been searching for an answer to this for the last few days but with no luck, so I thought I'd register here to see if anyone can possibly help.

All I've been able to find everywhere for this is examples of changing images when rolling over them or clicking them, and I don't need that.

What I need is a bit of javascript that will recognise some image paths on a page and replace those image paths with other ones.

It's for an ecommerce website on a certain platform, using a customer reviews section which outputs star images based on the customer's rating. So, the images used (which look awful) are, for example, "sourcehere/stars_5.gif", "sourcehere//stars_4.gif", and so on. Just 5 of them.

I want to design my own 5 images, upload those images, and then have the javascript replace the rubbish looking ones on the page with my own images.

I thought I'd be able to find something quite easily, but so far all I can find is examples of mouseover events and so on, and I don't need any of that, just the entire image replaced with my own image.

Can anyone help please? I'm a beginner with javascript so I'll need it spelled out to me! Thankyou for your time.

in the div class "done" it reads 13/34
i want to compare these to numbers like this

if (13 < 34){do something()}
else {return false;}

so i am trying to get each number by it self to compare with.

var did=m[1].getElementsByClassName("done")[1].innerText.replace(/\/.*/,"").value;
this line returns 13 correctly.

var need=m[1].getElementsByClassName("done")[1].innerText.replace(? ,"").value;
this ? the info that i need to get for the other number.
i know how to do it if it were a letter but can find the correct way being that it is a / instead.

Thx

Hi

I'm looking for a very simple script to replace one div with another. I've found a few but they seem overly complicated with features I don't need. I simply want to be able to click on a div and for it to be replaced with another div previously hidden. If someone could suggest a solution or point me in the right direction I'd really appreciate it.

Thanks

I found a regular expression that will strip my string of every html tag...

var stripped = htmlStr.replace(/(<([^>]+)>)/ig,"");

Well, I also want it to strip every thing between parentheses, square brackets, and replace " &# 160;" with a space.

It would be really cool if you could explain how to do this as well, because the stuff in the above code after "replace" confuses me. I have no idea how that's working.

First of all, I don't want to replace text in a form, or on click.

I'm writing up a design document in HTML, and I need an area to display code.
The < and > tags won't show up, obviously, but to make it easier on the programmer, I don't want him to have to manually put in &lt; and &gt; for each time it shows up.

I am aware that JavaScript has a replace function, but I am not familiar with JavaScript quite yet.

Is there a way to have JavaScript find the < and > in a certain div, and replace it with &lt; and &gt; on load?

I would appreciate your help so much, Its been frustrating me.

Does anyone know if it it possible to automatically replace any instance of & with 'and' using javascript when someone types into a text input?