|
JavaScript - Javascript Objects
Hello everybody am a JavaScript beginner.
here is a code making rollovers //////////////////////////////////////////////// window.onload=rolloverInit; function rolloverInit() { for(var i=0; i<document.images.length; i++) { if(document.images.parentNode.tagName=="A") { setUpRollover(document.images); } } } function setUpRollover(currentImage) { currentImage.outImage = new Image(); currentImage.outImage.src = currentImage.src; currentImage.onmouseout = rollOut; currentImage.overImage = new Image(); var source = currentImage.src; var sourceText = source.toString(); if(sourceText.indexOf("png")>0) { currentImage.overImage.src ="images/"+currentImage.id+"_on.png"; } else { currentImage.overImage.src ="images/"+currentImage.id+"_on.gif"; } /*currentImage.overImage.src ="images/"+currentImage.id+"_on.gif";*/ /*currentImage.overImage.src ="images/"+currentImage.id+"_on.png";*/ currentImage.onmouseover = rollOver; currentImage.clickImage = new Image(); if(sourceText.indexOf("png")>0) { currentImage.clickImage.src ="images/"+currentImage.id+"_click.png"; } else { currentImage.clickImage.src ="images/"+currentImage.id+"_on.gif"; } /*currentImage.clickImage.src = "images/"+currentImage.id+"_on.gif";*/ /*currentImage.clickImage.src = "images/"+currentImage.id+"_on.png";*/ currentImage.onmousedown = rollClick; currentImage.parentNode.childImage = currentImage; currentImage.parentNode.onblur = rollOutParent; currentImage.parentNode.onfocus = rollOverParent; } function rollOut() { this.src = this.outImage.src; } function rollOver() { this.src = this.overImage.src; } function rollClick() { this.src = this.clickImage.src; } function rollOutParent() { this.childImage.src = this.childImage.outImage.src; } function rollOverParent() { this.childImage.src = this.childImage.overImage.src; } //////////////////////////////////////////////// 1-I do understand "if iam right, lol" that here ///currentImage.outImage = new Image();/// and here ///currentImage.overImage = new Image();/// and here ///currentImage.clickImage = new Image();/// we are creating an image object "overImage" on the fly which still a property of currentImage object, to keep track and store the current image and new image src. but here ///currentImage.parentNode.childImage = currentImage;/// I am unable to see the point behind creating the childImage object -same rule applied here??? is it really a brand new independent object "still a property of the parent" created on the fly like before? and if so -what is is purpose here?? how the cildImage object is interacting here, what is its purpose? and how it is able to modify "actually change" the <a> object child node Image object "currentImage". it seems stupid question but its quiet simple ---///currentImage.parentNode.childImage = currentImage;/// here I have an object on the fly, a new Image object "childImage", that is Fine until now. ---///this.childImage.src = this.childImage.outImage.src;/// now how the childImage became able to change my parent "<A>" child "currentImage" src ??? how it "childImage" became displayable at all is is because of the assignment here ///currentImage.parentNode.childImage = currentImage;/// ??? Yes i assigned currentImage to the childImage, but based on my java programing concepts background each still independent objects refrences representing two different objects ---->and so based on that here is these functions rollOutParent(), rollOverParent() am supposed to say something like ***this.currentImage.src = this.childImage.src*** or ***this.childImage.src = this.childImage.outImage.src;***or whatever "i know thats wrong coding here am just giving example". ------------ am confused, how with this simple line of code currentImage.parentNode.childImage = currentImage; childImage became able to define the currentImage ? and if so, how this was achieved, hoe the Objects is being represented and how they interact in the core memory? Similar TutorialsHi If i was using c# i would use a generic list and add all my people objects to the list collection but how do i do this in jquery/javascript eg //container object var allObj= { }; //people object var people= { name:"fred",: age:00; }; How do I add many people objects to allObj (the amount of people added in not always the same) eg the final result is something like this allObj -person1 -person2 -person3 -person4 thanks Hello, Here is my situation. I have a java array generated from a JSP on the server side, and saved in the session. This array consists of objects (of say class X). How can I load this array into a javascript array so I can search for a this array based on attributes of the object? Thanks Hi, one of my js file is receiving a variable which is of type object. This object has some html texts. How can get the content of this object (something like value) in javascript? Thanks, Pavan Hi, Can i sort an array of objects in javascript?. I am having the value as Code: var myVarr = [{"name":"xyz","age":21},
{"name":"cde","age":25}].
The above array has two objects. I need to sort by age using javascript. Please help. Regards, anas This is a bit of a strange one. I have been trying to call a function in a child object from the parent object but the child seems to be going out of scope in onbeforeunload function. These function calls work outside of a onbeforeunload, so it only fails when called in onbeforeunload. I can fix it by making the child object a global but I was trying to avoid that. Anyone know why my childobject is out of scope when called in onbeforeunload? Notice I call that same function in windows onload event and it works fine. Here is the code (I have simplified as much as possible to just show the error): Code: <html>
<head>
<title>Broken Page</title>
<script language="javascript" type="text/javascript">
var myparent;
function windowLaunch()
{
myparent = new parent();
myparent.getchildvalue();
window.onbeforeunload = myparent.getchildvalue;
}
function parent()
{
this.mychild = new childobject("myinput");
this.getchildvalue = function()
{
var tmpval = this.mychild.returnvalue();
};
}
function childobject(thename)
{
this.myprop = thename;
this.returnvalue = function()
{
return (document.getElementById(this.myprop).value);
};
}
</script>
</head>
<body id="thebody" onload="windowLaunch();">
<div id="outerdiv">
<span title="This Input Box">My Input:</span><br />
<input id="myinput" style="width: 290px"/>
</div>
</body>
</html>
Hi, I am a begginer in javascript, please help on below I want to create an object with nested objects array like following: var country{ var states=new array(); } var state { city,pincode } this should be called like var city= country[0].state[0].city; any idea will be appreciated I was wondering if there are any sites dedicated to ending javascript objects using the prototype property to give them features like trimming string, removing elements of arrays by name, removing duplicates in arrays, etc. Granted I have functions to do this but there's probably a ton of other good ones out there. Most things I've seen are frameworks like JQuery (which is awesome) but it doesn't extend these objects.
I wrote a log function that took note of various function calls. Thinking that functions are first class objects, and objects have properties, I made the name of each logged function a property of that function, e.g., brightenInnerPara.name = "brightenInnerPara"; Every browser I tried (Firefox, MSIE, Opera, Chrome, Safari) accepted the assignment, no problem. In Firefox and MSIE, the result was what I wanted: brightenInnerPara.name == "brightenInnerPara" But in the others, the result was: brightenInnerPara.name == null Question 1. Which Javascript is correct here? I favor Firefox and MSIE, not merely because they were willing to give me what I wanted, but also because it makes no sense to accept an assignment statement without throwing an error and then give it a null semantics, like Chrome, Opera, and Safari did. I found a workaround, using assignments like this: brightenInnerPara.prototype.name = "brightenInnerPara"; To my surprise, that worked in every browser. But I don't know why. It seems that such assignments are enough to cause each function to have its own distinct prototype. Question 2. Just how inefficient is my workaround, and why does it work? function($) { $.fn.superfish = function(op){ var sf = $.fn.superfish, c = sf.c, } So I see the '.superfish' method being added to the object '$.fn'. I find it interesting that the first order of business is to declare 'sf' and stuff in to it some value '$.fn.superfish' which I do not fully understand. Also the statement c=sf.c How can 'c' be set to equal 'sf.c' when no 'sf.c' has been declared yet? Thanks! Good day, I have the following code: Code: var img = new Image(); img.myProperty = 'something'; I've tried Image.prototype.myProperty and a few other things. It seems IE just doesn't want me extending the Image object. Is there a known work-around? Thanks Greetings! This is actually a two part question from the html source I attached as a .txt document (too big for the post). 1) How can I get the name of an object. I took my failed attempt in the function named disableJobStream: Code: function disableJobStream(obj)
{
if((obj.value == "completed") && (getRadioCheckedValue("shift") == "2"))
{
if(obj.name == "artprogs")
{ document.shiftreport.artprogs.disabled = true; }
}
<select style="100px;" name="artprog_stat" OnChange="disableJobStream(this)"><option style='background-color:white;' value='none'selected='selected'>None</option>
<option style='background-color:red;' value='stopped'>Stopped</option>
<option style='background-color:yellow;' value='running'>Running</option>
<option style='background-color:green;' value='completed'>Completed</option>
</select>
2) Once I put my form through validation any of the fields that I disabled become enabled again. How would I go about keeping that from happening? Page is too large to post and too large to put up as an attachment! Thanks for your help! Is it possible to create an array of objects? I require a two dimensional array of objects. Thanks! Hello there folks, First time poster, so please be gentle I am ok with using objects creating classes if someone else defines, but when it comes to defining my own, I hit a nasty brick wall... I am using an XML/XSLT wrapper called Sarissa to help with programming a utility to transform XML into HTML in different views. For this to happen, I have created a Loader class which loads in XML required. I am aware of prototyping for binding methods to objects (as opposed to replicating the same method every time an instance is created)... The aim being I want to create a progress bar for the essential files that need to be loaded in. Presently I have them load in Synchronous mode just to get the utility working, which I know is poor, so would like to address it. So can someone answer me this: I understand why this works: Code: var SWMU = new Object();
SWMU.stylesheets = new Object;
SWMU.joblot = null;
SWMU.cache = new Object;
SWMU.filtering = new Object;
SWMU.locns = null;
function Loader(sXml, sTitle) {
this.doc = Sarissa.getDomDocument();
this.doc.load(sXml);
this.doc.summary = sTitle;
this.doc.onreadystatechange = function() {if(this.readyState)
{alert(this.summary + " state change to..." + this.readyState);} else
{alert(this.summary + " state change to..." + this.doc.readyState);}
}
}
function async() {
SWMU.stylesheets[0] = new Loader("swmu_test/swmu_berthing.xsl", "Main SWMU Stylesheet");
SWMU.stylesheets[1] = new Loader("assets/xsl/controls.xsl", "Drop down boxes");
}
function _init() {
async();
}
as it recreates the "this.doc.onreadystatechange" anonymous function everytime an instance is created (which is yuck). However, when I do this (using prototype)... Code: var SWMU = new Object();
SWMU.stylesheets = new Array;
SWMU.joblot = null;
SWMU.cache = new Object;
SWMU.filtering = new Object;
// Now define the Loader object
// Create the loader method for dealing with items loaded
function Loader(sXml, sTitle) {
this.doc = Sarissa.getDomDocument();
this.doc.load(sXml);
this.doc.summary = sTitle;
}
function rHandler() {alert(this.summary + " State changed to... "+this.readyState);}
// Create the request handler
Loader.prototype.doc = {};
Loader.prototype.doc.onreadystatechange = rHandler;
function async() {
SWMU.stylesheets[0] = new Loader("swmu_test/swmu_berthing.xsl", "Main SWMU Stylesheet");
SWMU.stylesheets[1] = new Loader("assets/xsl/controls.xsl", "Drop down boxes");
}
function _init() {
async();
}
Nothing happens and no errors are thrown, though there should be an alert box everytime there is state change to the progress of a file loading. Can someone help me with this? Apologies if this is on the basic side, but it has been causing me a headache all week, and I can not find any answers on this. Shaun Hi there, I have a very strange issue using dynamic scripting and iframe. It looks like when when iframe is loaded (i.e. onload method is triggered) all js objects that were sent to iframe before disappear? To clarify... I set iframe.scr from java script that caused it to connect to the server. After connection is established I start sending JS code to it (including some JS objects). At some point connection to iframe is closed (and onload method is called). Later on I reconnect (i.e. set src property again), and try to issue method calls on the JS objects that were sent in earlier session. None of these methods get triggered. Did anyone experienced similar problems? Is there a workaround? (I.e. is there any way I can send register JS Objects globally when sent through iframe?). Thanks for all your help, Ed I'm trying to reuse some code in a different context to do a different job. The code to be reused contains hundreds of lines similar to a = new b.c.d(e,f) with different value for e and f. I need to create a new user defined object with the structure b.c.d. I've made numerous attempts along the lines of: Code: function d (e, f) {
this.e = e;
this.f = f;
}
function c () {
this.d = d (e, f);
}
function b () {
this.c = c;
}
var a = new b.c.d("test", "message");
with various permuations of functional declarations. However I get error message "Object expected" or "b.c.d is null or not an object" at the final line of the example. It works with the test line var a = new d("test", "message") but not when I start to build up the expression. How should I define of b.c.d? Hi All I thought it was about time to actually learn Javascript rather than pretend I know it, so I'm new to Javascript. I've been reading Javascript 'The Good Parts' and have watched a few google videos on Youtube. So I came across prototyping which seems to be quite fundamental to JS but is quite awkward to use. I am trying to avoid the use of the 'new' keyword and limit my application to one Global variable, as this can improve the JS scripts performance, reliability and security. In essence I'm just trying to make a simple MsgBox object that has a method called 'alertMe', which in turn simply shows an alert box with 'Hello' If this is not very clear then say so as trying to explain something you don't fully understand is quite hard. Here's my code, doesn't alert when I called the object. Have a look Code: var MyLib = {};
MyLib.MsgBox = function(){
//Object methods
MyLib.MsgBox.prototype.alertMe = function(){
alert('Hello');
};
};
MyLib.MsgBox.alertMe();
Any help and pointers will be very appreciated. Regards, Magnetica I'm having a spot of trouble in making my functions work and my book seems to be pure rubbish. I'm sure that the error is purely syntax, although it may be something more. Code: <script type="text/javascript" src="flowers.js"></script>
<script type="text/javascript">
function pageSetup() {
var today = new Date(); // this creates a date object with today's date
var banner = displayBanner(today); // *should* call the displayBanner function
var days = calcDaysToSale(today); // *should* call the function using today's date
document.sale.saleMessage.value = days; // *should* set the value to days.
// Obviously none of it works.
}
</script>
This is the code working with the script contained in the html file. I'll post the full page at the bottom. The following code is the JavaScript code. The first function isn't made to provide full functionality at the moment, I'm trying to get the rest of it working. Code: function displayBanner(currentDate) {
if (currentDate.getMonth() == 2)
imgSrc = "winterLogo";
return ("<img src='" + imgSrc + ".gif'>");
}
function calcDaysToSale(currentDate) {
var saleDay = new Date();
saleDay.setDate(15); // sets the sale date to the 15th of the current month
// Subtracts the days remaining until the sale.
// If the number is negative, the sale is over.
var Days = saleDay.getDate()-currentDate.getDate();
if (Days < 0) {
return "The sale has ended.";
}
else {
return Days;
}
}
I have tried to Google the problem and I have also tried to look it up in my book. I simply don't know the right terms to Google, and as I said the book is rubbish. I don't know why the Code: document.sale.saleMessage.value = days; doesn't work for this. Oh well, I'll learn quickly I suppose. Here is the full HTML code: Code: <!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" />
<title>Carol's Flowers</title>
<link href="flowers.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="flowers.js"></script>
<script type="text/javascript">
function pageSetup() {
var today = new Date(); // this creates a date object with today's date
var banner = displayBanner(today); // *should* call the displayBanner function
var days = calcDaysToSale(today); // *should* call the function using today's date
document.sale.saleMessage.value = days; // *should* set the value to days.
// Obviously none of it works.
}
</script>
</head>
<body class="oneColLiqCtrHdr">
<div id="container">
<div id="header">
<p><img name="myBanner" src="banner" id="myBanner" alt="Carol's Flowers" />
<!-- end #header -->
</p>
<div id="links"><a href="#">Home</a> | <a href="#">General Arrangements</a> | <a href="#">Seasonal Designs</a> | <a href="#">Custom Orders</a> | <a href="#">Location</a></div>
</div>
<div id="mainContent">
<table id="mainTable">
<tr>
<td width="201"><h1><img src="Flowers.JPG" alt="Random Flowers" width="200" height="255" /></h1></td>
<td width="687">
<p>Here at Carol's Flowers, we believe that there is a perfect floral arrangment for every occasion! Take a look around and see if there is anything you like. If we don't already have it, then we will create it for you!</p></td>
</script>
</tr>
</table>
<!-- end #mainContent --></div>
<div id="footer">
<p> <form name="sale" id="sale">
Days Until Mid Month Madness Sale :
<input type="text" name="saleMessage" id="saleMessage" /></form></p>
<!-- end #footer --></div>
<!-- end #container --></div>
<!-- I am trying to run the script here -->
<script type="text/javascript">
pageSetup();
</script>
</body>
</html>
Hi, I am trying to detect a users browsers and output a different code based on browser. I found this code online that uses the object detection method and it works. When I document.write(BrowserDetect.browser) it outputs Chrome, (which is what I am using). The code can be found he http://www.quirksmode.org/js/detect.html So I can't understand why the following code does not work? It ouputs the "not" in the else statement. I believe that BrowserDetect is an object and the .browser at the end is a property of the object. Can one not make an object a variable? or make an object a string? oh and BTW there is a bunch of javascript that creates the browserdetect object that can be found on the site above, but I thought it would be too unwieldy to post here. Thanks. The following script outputs: Chrome Not Working <script type="text/javascript"> document.write(BrowserDetect.browser); var browser="BrowserDetect.browser"; if(browser=="Chrome") { document.write(" Working"); } else { document.write(" Not working"); } </script> I am able to do the following; Code: alert(myObject.Income.EESA.Name); However I'm looking at Code: alert(myObject.Income[0].Name); Or even better, not the full name, just "EESA". I need to loop through as you can see at the end of this script what I'm working on. Code: <script type="text/javascript">
var EESARate = 289.3;
var DLARate = 111.20;
var CARate = 61.35;
var SkyCost = 54.75;
var PerfectHomeCost = 28.17;
var CreditExpertCost = 14.99;
var UnitedUtilitiesCost = 8.13;
var BTCost = 57.18;
var AdobeCCCost = 46.88;
var TVLicenceCost = 6.06;
var GasCost = 10.00;
var ElectricCost = 20.0;
var ServerPackageCost = 9.99;
var USDValue = 123; //Fetch the value
var myObject = {
"Income": {
"EESA": {
"Name": "Enhanced Employment and Support Allowance",
"Amount": {
"GBP": EESARate,
"USD": EESARate * USDValue
},
"Frequency": {
"When": "14",
"Next": "30/10/2014"
},
"Description": "",
},
"DLA": {
"Name": "Disibility Living Allowance",
"Amount": {
"GBP": DLARate,
"USD": DLARate * USDValue
},
"Frequency": {
"When": "7",
"Next": "Wednesday"
},
"Description": "",
},
"CA": {
"Name": "Carers Allowance",
"Amount": {
"GBP": CARate,
"USD": CARate * USDValue
},
"Frequency": {
"When": "7",
"Next": "Saturday"
},
"Description": "",
},
},
"Bills": {
"Sky": {
"Name": "Sky",
"Amount": {
"GBP": SkyCost,
"USD": SkyCost * USDValue
},
"Frequency": {
"When": "30",
"Next": "XX/XX/XX"
},
"Description": "",
},
"PerfectHome": {
"Name": "Sky",
"Amount": {
"GBP": PerfectHomeCost,
"USD": PerfectHomeCost * USDValue
},
"Frequency": {
"When": "7",
"Next": "Wednesday"
},
"Description": "",
},
"CreditExpert": {
"Name": "Experian Credit Expert",
"Amount": {
"GBP": CreditExpertCost,
"USD": CreditExpertCost * USDValue
},
"Frequency": {
"When": "30",
"Next": "XX/XX/XX"
},
"Description": "",
},
"UnitedUtilities": {
"Name": "United utilities",
"Amount": {
"GBP": UnitedUtilitiesCost,
"USD": UnitedUtilitiesCost * USDValue
},
"Frequency": {
"When": "7",
"Next": "Wednesday"
},
"Description": "",
},
"BT": {
"Name": "British Telecomunications",
"Amount": {
"GBP": BTCost,
"USD": BTCost * USDValue
},
"Frequency": {
"When": "30",
"Next": "XX/XX/XX"
},
"Description": "",
},
"AdobeCC": {
"Name": "Adobe Creative Cloud Suite",
"Amount": {
"GBP": AdobeCCCost,
"USD": AdobeCCCost * USDValue
},
"Frequency": {
"When": "30",
"Next": "XX/XX/XX"
},
"Description": "",
},
"TVLicence": {
"Name": "Television Licence",
"Amount": {
"GBP": TVLicenceCost,
"USD": TVLicenceCost * USDValue
},
"Frequency": {
"When": "30",
"Next": "XX/XX/XX"
},
"Description": "",
},
"Gas": {
"Name": "Eon Gas",
"Amount": {
"GBP": GasCost,
"USD": GasCost * USDValue
},
"Frequency": {
"When": "7",
"Next": "Wednesday"
},
"Description": "",
},
"Electric": {
"Name": "Eon Electric",
"Amount": {
"GBP": ElectricCost,
"USD": ElectricCost * USDValue
},
"Frequency": {
"When": "7",
"Next": "Wednesday"
},
"Description": "",
},
"ServerPackage": {
"Name": "1&1 Unlimited Plus (12 mo. term)",
"Amount": {
"GBP": ServerPackageCost,
"USD": ServerPackageCost * USDValue
},
"Frequency": {
"When": "30",
"Next": "XX/XX/XX"
},
"Description": "",
},
},
};
var IncomeTotal = 0;
for (var k in myObject.Income) {
if (myObject.Income.hasOwnProperty(k)) {
++IncomeTotal;
}
}
alert(myObject.Income.EESA.Name);
document.write('<table>')
for(i = 0; i < IncomeTotal; i++){
document.write('<tr>')
document.write('<td>row ' + (i+1) + ', column 0</td>')
document.write('</tr>')
}
document.write('</table>')
var TotalBills = 0;
for (var k in myObject.Bills) {
if (myObject.Bills.hasOwnProperty(k)) {
++TotalBills;
}
}
//alert(TotalBills);
</script>
|
|||||||