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JavaScript - Techincal Question About Object And Constructors
This is a constructor function.
PROC will be an instantiation of another constructor. It will have a copy of GLBS. function _CALC_ELEMENTS(ELEM, GLBS, PROC) // PROC will also have a copy of GLBS. So, techincally, how could I access the copy of GLBS in PROC, via instance of _CALC_ELEMENTS. If I can do this, I do not need to include it directly. (GLBS is yet another object instantiated via constructor) I am just concerned that there are two copies when only one is necessary. Thanks for thoughts on this JK Similar Tutorialsif location is a property of window object that returns a string and im appending .indexOf() to location why is it not working?
I was going through an article on JavaScript objects on "http://www.howtocreate.co.uk/tutorials/javascript/javascriptobject" and there I read Quote: Intrinsic objects - variable types with constructors. * Array * Boolean * Date * Function * Image * Number * Object * Option * Regular Expression * String does it mean that, whenever I want to use any of these objects, I have to create it using new and only then I can use its properties or methods ? 1) There are other objects like document, history, location, navigator, parent and screen. If objects which need to be created using constructor are called intrinsic objects , then what are other objects which can be used without constructor are called as ? Array, Boolean, Image, Date etc all start with capital letter. While document, history, navigator etc start with lower case letter. Why is that ? Is there any difference between objects that start with upper case and those start with lower case ? Are they known by different names ? Thanks My question is commented in the script: Code: function Love(){
var req = {
ring : 'gold',
money : 'a lot',
commitment : 'long-term'
}
this.loveReqs = function(){
return req;
}
}
var you = new Love();
var details = you.loveReqs();
details.ring = "silver";
console.log(details.ring);
var me = new Love();
var details = me.loveReqs();
console.log(details.ring); // why does this return gold and not silver if req is passed by reference and we already changed its value above and so it's pointing to the same memory position?
Hello, I'm trying to write my class with member properties and functions like below. What I want to learn is that is there any problem to use prototype object in the class that we want to use with it? I asked because I generally see that prototype object definition and member functions and properties created outside of the class unlike my class that I wrote like below. Is there any problem writing my class like below? Thanks. Code: function Point()
{
Point.prototype.x = this._x;
Point.prototype.y = this._y;
function _setX(x)
{
this.x = x;
}
Point.prototype.setX = _setX;
function _setY(y)
{
this.y = y;
}
Point.prototype.setY = _setY;
function _show()
{
alert(this.x + this.y);
}
Point.prototype.Show = _show;
}
function callMyClass()
{
var p = new Point();
p.setX(3);
p.setY(5);
p.Show();
}
The following code snippet: (this.inputArray is already defined and initialized prior to this code sequence) if(this.inputArray.length >= 0) { this.inputArray[this.inputArray.length] = new Object(); this.inputArray[this.inputArray.length].type = 'pcDisp'; this.inputArray[this.inputArray.length].data = a; } the first line in the code block should create a new array item and initialize it with the various assigments in the next lines. But Firefox complains "this.inputArray[this.inputArray.length] is not defined". This is very disconcerting because the code has to create array items with different data based on conditionals. So I must be able to automatically create new items as necessary. I thought that javascript had 'late binding', but maybe that doesn't apply here. So, does anyone have a clue for me? function get_price() { var the_price=1000; if (this.speed=="500MGz") the_price+=200; else the_price+=100; if (this.hdspace=="15GB") the_price+=50; else the_price+=25; if (this.ram=="128MB") the_price+=150; else the_price+=75; return the_price; } function computer(speed,hdspace,ram) { this.speed=speed; this.hdspace=hdspace; this.ram=ram; this.price=get_price; } var work_computer=new computer("2GHz","80GB","1GB"); var home_computer=new computer("1.5GHz","40GB","512MB"); var laptop_computer=new computer("1GHz","20GB","256MB"); var work_computer_price=work_computer.price(); var home_computer_price=home_computer.price(); var laptop_computer=laptop_computer.price(); ___________________________________________________ In the above code, the line I'm having trouble with is marked red. Why is it that when I call the method using ... this.price = get_price; It works fine. But if I assign the object this.price with like this... this.price = get_price(); I get an error? Isn't get_price() a function? So shouldn't the parenthesis be included when the method is called? Why are we suppose to leave out the parenthesis?! I'm confused. Thanks! Hi, every time I try and alert: [ { number:0, secondnumber:0 }, { number:2, secondnumber:1 }, { number:1, secondnumber:2 } ] it just shows [object object], [object object], [object object]. Why is this and what can I do to make the record be shown as it is above in an alert? Thanks. I can't get any info from Firebug except that one line, uncaught exception [object Object]. The code fully worked, then I needed to make it dynamically create Sortables from the scriptaculous library based on how many X were in a table in my database, which I've done, and I'm thinking it may be a simple slight parse error of some type, I'm not too good with Javascript, because now my script barely works. I've double checked the script's source code, the PHP variables are exactly what they should be. Code: print<<<HERE
Sortable.create('sortlist$box', { tag: 'img', overlap:'horizontal',constraint:false, containment: $list, dropOnEmpty: true,
onChange: function(item) {
var list = Sortable.options(item).element;
if(changeEffect) changeEffect.cancel();
changeEffect = new Effect.Highlight('changeNotification', {restoreColor:"transparent" });
},
onDrop: function(item) {
var thing=Sortable.options(item).element.identify();
var anchors = document.getElementById(thing).childNodes.length-2;
if(anchors > 20){
alert('This box had 20 creatures in it already, your last action has not been saved.');
window.location.reload();
}
else{
new Ajax.Request("saveImageOrder.php", {
method: "post",
parameters: { data: Sortable.serialize("sortlist$box") }
});
}
}
});
HERE;
$box++;
}
?>
});
</script>
if you solve this I'll send ya $10 via paypal I created a method for displaying an object's properties: Code: renderfunction = false;
function showProperty (object, property)
{
document.write ('<td class="type">' + (typeof object[property]) + '</td>'
+ '<td class="name">' + property + '</td>');
document.writeln('<td class="value">' +
(
(typeof object[property] != 'function')
? object[property]
:(
(property != 'showProperties')
? (
renderfunction
? object[property]()
: ('<span class="self">NOT RENDERED</span>')
)
: ('<span class="self">THIS</span>')
)
)
+ '</td>');
document.writeln('<td class="hasOwnProperty" >'
+ (
object.hasOwnProperty(property)
? "Local"
: "Inherited"
)
+ '</td>');
if (typeof object[property] == 'function')
{
document.writeln ('<td class="function">' + object[property] + '</td>');
}
else
{
document.writeln ('<td class="function"> </td>');
}
}
As long as renderfunction = false, the object is fine coming out of this function. However, if I change renderfunction to true, all my properties become undefined. Why isn't this working as I expect it to? How should I fix it? Thanks in advance, -Brian. Hi all, I'm stumped on finding a way in javascript to create an object factory whose instances are also object factories. In short I want something like that below, but no joy ... any clues? Code: function createClass () {
return new createClass()
function createClass() {
return new createInstance ()
function createInstance () {
//Default properties, values and methods which might later be extended
}
}
}
var createDoor = createClass();
var door1 = createDoor();
var door2 = createDoor();
var createChair = createClass();
var chair1 = createChair ();
var chair2 = createChair ();
Ignore post (if mod, please delete)
Hello together! I generate html code with jsp. In that jsp there a several framesets and frames. And yes i know, frames are not really up to date but it's an old program and i have to deal with it now. Anyway, in the top frameset i have an onload attribute like onload="load()". In the function load i want to access the Element.prototype object. But unfortunately typeof Element gives me "undefined". So i looked a little deeper and found that window.toString() gives me "[object]" and not as expected "[object window]" so somehow my window doesn't know that its construcor is Window. window.construcor is "undefined" as well. And i don't have access to the Element object. I really don't know where the error could be. When the page is loaded and i access the same window over the console, then everything is right. But in my function a can't get access to the objects i need. I also don't know what part of the code could be useful to post here, but maybe someone had a similar problem before? i should say that this problem only occurs in IE8. In IE9 it works perfectly. Has anyone any idea?? I'm writing a program that involves a network of interconnected nodes (or simply objects in my example below). It depends on being able to access properties of an object's linked objects (a bit oddly worded, sorry)... Problem is I'm not sure how to properly access those properties... see below please. <script> //This is an example of a problem im having in my own code... //I want to access the name of the object within the links array wintin the object... var objA = {name: "Object A", links: [objB, objC]}; var objB = {name: "Object B", links: [objC, objD, objE]}; var objC = {name: "Object C", links: [objB]}; var objD = {name: "Object D", links: [objE]}; var objE = {name: "Object E", links: [objD]}; //ex: I want to access the name of Object A's first link... console.log(objA.links[0].name); </script> I'm hoping to get "Object B"... But instead I get: TypeError: Result of expression 'objA.links[0]' [undefined] is not an object. Is there another way around this? Any thoughts are appreciated. Hello. Is there any way to get the variable name of an object from inside the object? E.g. PHP Code: function Bla(){ this.write = function(){ document.write(<objectname>); } } obj1 = new Bla(); obj1.write(); //Outputs obj1 Here is my script: PHP Code: function myTimer(seconds, obj){ this.seconds = seconds; this.obj = obj; this.startTimer = function(){ if(this.seconds>0){ this.seconds--; this.obj.innerHTML = this.seconds; this.timer = setTimeout("Timer.start()",1000); } } } Timer = new Timer(10, obj); Timer.startTimer(); Now the problem is that the variable that contains the object must be named "Timer". This way I cannot create new timer objects with different variable names I have tried: this.timer = setTimeout("this.start()",1000); but it doesn't work. That's why it would be good to detect the variable name and instead use something like this: this.timer = setTimeout(varname+".start()",1000); I would rather not have to pass the variable name through a parameter like this: Timer1 = new Timer(10, obj, "Timer1"); Thanks in advance. Quote: menu: function( a, b ) { $( b ).observe( 'click', function( event ) { event.stop(); if( $( a ).visible() ) { $( a ).hide(); $( b ).removeClassName( 'selected' ); document.stopObserving( 'click' ); } else { $( a ).show(); $( b ).addClassName( 'selected' ); document.observe( 'click', function( e ) { if( e.target.id != a && e.target.id != b && !Element.descendantOf( e.target, $( a ) ) ) { $( a ).hide(); $( b ).removeClassName( 'selected' ); document.stopObserving( 'click' ); } }); } }); $$( '#' + b + ' > a' ).each( function( element ) { element.observe( 'click', function( event ) { $( a ).hide(); $( b ).removeClassName( 'selected' ); document.stopObserving( 'click' ); }); }); } This work's perfrect accept when i use it with others on the menu it leaves the other ones open, how do i get it to close the open one when i open a new menu.. Thanks. I am trying to troubleshoot my javascript function below. Code: <script type="text/javascript">
function txtboxfill(fillobj) {
var rChar=String.fromCharCode(13);
var myVal = "To: " + this.form.to.value + rChar;
myVal = myVal + "From: " + this.form.from.value + rChar;
myVal = myVal + "Subj: " + this.form.subj.value + rChar + rChar;
myVal = myVal + "Message: ";
fillobj.value = myVal;
}
</script>
Then I have a text box input field with an Code: <input type="text" id="tp" name="to" size="34" class="totext" onkeyup="txtboxfill(this.form.msg_area);"> and when I enter text in this field it gives me a 'this.form.to' is null or not an object and does not populate the textarea. BTW, msg_area is the id of my textarea. Thank you. Greetings, I have a floating object that work find within my page. However, I would like to only show after a button is clicked. Any ideas how to do this. Thanks Hi All, (Another Post LOL) Ive been getting alot of help with js recently THANKS! One last thing and i shouldnt be on here for a while How would i go about doing this Code: <object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="750" height="550" codebase="http://active.macromedia.com/flash4/cabs/swflash.cab#version=4,0,0,0"> <param name="movie" value="SWF/helicopter.swf"> <param name="quality" value="high"> <param name="menu" value="false"> </object> into JS using .innerHTML = "Above Stuff"; I always get an error + i dont know how im going wrong with the quotes :S ANY HELP (GOOD STUFF); Thanks In Advance, Jamie. NOM NOM NOM! Hello, below you will find two objects, background and photo1, which I need help cleaning up a bit. This will eventually be imported using Json but for now during development it sits as is in my script. I need help with a couple things: - You will notice the 'val' property is identical in both objects. How can I move this into an outside function that each object can share? I'm having trouble bc I couldn't get 'this' to work outside of its current context. - Second, how can I restructure this so that I can instantiate a new object. So if I wanted to add a new layer I'd like to do something like importLayers.push[new Layer('photo2')] Code: var importLayers = {
background: {
layerType: 'background',
index: 0,
layerContent: {
content: function() {
return $(element).find('#background_Content');
},
width: 850,
height: 530,
xPos: 0,
yPos: -150,
skewX: 0,
skewY: 0,
angle: 0,
originX: function() { return (this.sWidth() / 2); },
originY: function() { return (this.sHeight() / 2); },
scaleX: 1,
scaleY: 1,
sWidth: function() { return this.width * this.scaleX; },
sHeight: function() { return this.height * this.scaleY; },
aspect: 0,
opacity: 100,
val: function(prop, val) {
switch(prop)
{
case 'width':
if(plugin.constrain)
this.scaleX = this.scaleY = val / this.width;
else
this.scaleX = val / this.width;
break;
case 'height':
if(plugin.constrain)
this.scaleY = this.scaleX = val / this.height;
else
this.scaleY = val / this.height;
break;
case 'angle':
this.angle = val;
}
buildTransformation(this, this.content());
}
},
},
photo1: {
layerType: 'photo',
index: 1,
layerContent: {
content: function() {
return $(element).find('#photo1_Content');
},
width: 1920,
height: 1280,
xPos: 0,
yPos: 0,
skewX: 0,
skewY: 0,
angle: 0,
originX: function() { return (this.sWidth() / 2); },
originY: function() { return (this.sHeight() / 2); },
scaleX: .15625,
scaleY: .15625,
sWidth: function() { return this.width * this.scaleX; },
sHeight: function() { return this.height * this.scaleY; },
aspect: 0,
opacity: 100,
val: function(prop, val) {
switch(prop)
{
case 'width':
if(plugin.constrain)
this.scaleX = this.scaleY = val / this.width;
else
this.scaleX = val / this.width;
break;
case 'height':
if(plugin.constrain)
this.scaleY = this.scaleX = val / this.height;
else
this.scaleY = val / this.height;
break;
case 'angle':
this.angle = val;
}
buildTransformation(this, this.content());
}
},
}
}
Code: function globals()
{
this.states = "";
}
now I can: Code: globals.states = .... how to extend first code to be able: Code: globals.states.something = .... ? |
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