Giving AddEventListerner An Anonymous Function?

Nov 3, 2011

var name = "good";
load_image( name );
function load_image( name )


I've tried giving addEventListerner an anonymous function

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JQuery :: Calling An Anonymous Function?

Feb 3, 2011

I have a problem with understanding jQuery. In my case I have this JS file with following content (see below). This is an anonymous function, isn't it? The problem is this line:


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Getting Return Value From Post Anonymous Function

Jan 8, 2011

I have been struggling with a form wizard all day. I'm using jquery stepy (form wizard) along with validation plugin. To cut a long story short, my first step is to get MySQL connection from form controls details. On submit ('next' button) a check is made on an empty hidden control ('hid').

rules: {
hid: {
required: function(){
return checkDBData();
messages: {
{required: 'SQL not available'},

So, if the function checkDBData passes, false should be returned, so that the form can progress to the next step. If the connection details fail, true is returned so that an error msg is posted.

Here's the checkDBData function:
function checkDBData(){
var host = $('#mysql_host').val();
var username = $('#username').val();
var password = $('#password').val();
var dbname = $('#dbname').val();

{"host": host,"username": username, "password": password, "dbname": dbname},
if(msg.required == false){
return false;
return true;

The return values don't find their way back to the rules. However, if I hard code false and true to the function...
function checkDBData(){
var host = $('#mysql_host').val();
var username = $('#username').val();
var password = $('#password').val();
var dbname = $('#dbname').val();

{"host": host,"username": username, "password": password, "dbname": dbname},
if(msg.required == false){
return false;
return true;
return false; //or return true for testing purposes
This works. I assume it's due to the asynchronous nature of the ajax call.

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Creating Anonymous Function With Variable?

Mar 20, 2010

I'm having trouble with something that I can't explain outside of an example. Code:

$js_info_tabs = json_encode($valid_array);
$script = <<<JAVASCRIPT
<script type="text/javascript">//<![CDATA[
function changeTo(id) {


I have the code this way in order to consolidate it since I would prefer to do that instead of checking the selected ID and manually checking against all possible IDs (which works flawlessly, it just takes up about 5x the lines and is not modular). What I have above also works, but there is one fatal flaw:

It seems like the anonymous function that is the onclick for each unselected element becomes "return changeTo(tab + '_id')", but I don't want it to be that. I want the argument to actually be what tab is instead of the variable.

What ends up happening is that after changeTo() is called for the first time, any element you click will result in the last element being the selected one, as if it's using the final value of tab as its return value.

This doesn't make any sense, though, since tab is local, and deleting it before the function exists doesn't work. Deleting elem at the end of the for loop doesn't work. I honestly don't understand what's going on or why it doesn't set the new onclick value correctly.

Basically I just want changeTo(tab + '_id'); to turn into changeTo('MYID_id'); instead, but it simply doesn't do that and I can't figure out a way how.

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Returning ResponseXML, Set Within An Anonymous Function, Only Once ReadyState = 4

Dec 4, 2006

I have several functions with code along the lines of:

var xmlDoc = requestXML("ajax.asp?SP=SelectRelatedTags&tag=" +

The requestXML() function includes the code:

var xmlDoc = null;
http_request.onreadystatechange = function() {
if (http_request.readyState == 4) {
if (http_request.status == 200) {
xmlDoc = http_request.responseXML;
} else {
alert('There was a problem with the request.' +
}}};'GET', url, true);
return xmlDoc;

However, the last line (the return) executes before the readyState
reaches 4. How do I return the xmlDoc to the functions only once the
xmlDoc has been assigned? I tried putting the return statement in a
while loop with the condition that the readyState must = 4 - this
worked, but makes the browser popup a message saying the script is
slowing down the system.

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Passing Anonymous Function From SetTimeout() - IE Doesn't Like - FF Does

Jun 6, 2009

I did search the forums but couldn't seem to find anything on this specifically. I basically need to pass a key event and a 'name' to nameCheck() after 3 seconds. This works fine in Firefox but Internet Explorer gives the error: Member not found. I'm more of a PHP guy than a JS one

<input type="text" onkeyup="nameCheckTimer(this.value, event)" value="" />
function nameCheckTimer(name, evt) {
setTimeout(function(){return nameCheck(name,evt)}, 3000);
function nameCheck(name, evt) {
//need name and the key event to be available here. I have code to handle the key codes which works fine

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Passing 'this' To Anonymous Function In Event Listener

Jun 10, 2010

I'm working with nested functions and trying to pass a 'this' value to an anonymous being used in an assignment for an event listener.So, this should plop a button inside our DIV and when clicked I'd like it to run the alert-ding; unfortunately it seems to want to run the function as defined under the buttons object which doesn't work out too well.

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JQuery :: Pass Reference To An Object To Anonymous Function?

Aug 2, 2010

I would like to know how to pass in a reference of this to anonymous function so I can access parameters from anonymous. Here is my code:


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CurrentAge Function Not Giving Appropriate Output

Apr 22, 2010

I'm fairly new to writing script and so can only assume I have got something incorrect because the 'ages' are failing to change by -1 when the month and day is greater than the current date.

function currentAge(value){
var theDOB = value;
var theDOB = theDOB.split('/');
var DOBday = theDOB[0];
var DOBmonth = theDOB[1];
var DOByear = theDOB[2];

var todaysDate = new Date()
var yr = todaysDate.getFullYear();
var mth = todaysDate.getMonth() +1;
var dayy = todaysDate.getDate() +1;
var theAge = (yr -DOByear);
var yearBefore = (theAge -1);

if (mth <= DOBmonth && dayy < DOBday) {
return yearBefore;
else {
return theAge;

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When Closures, Loops, Function References, And Anonymous Functions Interact

Oct 16, 2010

I am confused about the true difference between the two below examples.

first example:

// Demonstrating a problem with closures and loops
var myArray = [“Apple”, “Car”, “Tree”, “Castle”];
var closureArray = new Array();


Here we iterate through the length of myArray, assigning the current index of myArray to theItem variable. We declare closureArray 4 times as an anonymous function. The anonymous function in turn declares the predefined write() function, which is passed parameters. Since write() is in closureArray() a closure is created??? During each iteration, theItem is reassigned its value. The four closures reference this value. Since they reference this same value and since this value is reassigned ultimately to the value of the fourth index position, tHe time we execute closureArray later on, all four closures output the same string. This is because all four closures are within the same scope "the same environment" and therefore are referencing the same local variable, which has changed.

I have a couple of problems with this example:

1) I thought a closure is a function that is returned - the inner function is not returned above.

2) theItem is not even a local variable of the parent function (closureArray) - I thought in order for a closure to work, the inner function only accesses the local variables of the outer function, but in this case the local variable is defined OUTSIDE of the parent function.

3) the "the four closures are sharing the same environment." The thing is even in the second example, they are sharing the same environment.

Second example:

// A correct use of closures within loops
var myArray = [“Apple”, “Car”, “Tree”, “Castle”];
var closureArray = new Array();


Here we iterate over the length of myArray (4 times), assigning the index of myArray to theItem variable. We also return a function reference to the closureArray during each iteration (closureArray[i]), where i is index number so we assign 4 functon references. So when we iterate through myArray, we immediatelly call the writeItem() fucntion passing an argument of theItem at its current value. This returns a child anonymous function and when that child function is called, it will execute a block that calls the predefined write() method. We assign that returned anonymous function to the variable closureArray. Hence, closureArray holds a reference to that anonymous function. So closureArray during each iteration holds a reference to the anonymous function and we later call closureArray, which in turn calls the anonymous function, therefore calling the predefined write() function to output the local variable of the parent function. This outputs each distinct index of myArray.

This is because since we created the closure, when we call writeItem, passing theItem argument, since theItem is a local variable of the parent function of the closure, it is never destroyed when we later call closureArray (the reference to the child anonymous function)? Yet weren't we using a closure in the first example as well? So whey wasn't those variables preserved?

I don't think it has anything to do with assigning a returned anonymous function to closureArray. Even though an anonymous function creates a new memory position in the javascript engine, therefore not overwriting the other function references we create during the iteration, it's still referring to a local variable declared outside the reference. So if it's about the closure retaining value of parent's local variable even after exiting the parent function allowing for the current indexes to be preserved, then why did the closure in the first example fail to retain each index?

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Create An Anonymous Function For Onchange Event Of File Field?

Feb 28, 2010

I am trying to create an anonymous function for onchange event of file field, so that when a file is selected, the covering text field gets that value. I know how to accomplish this by adding onchange="", but I'd prefer not do that. The code that I have almost works, except that the function in the for loop can't call on the "i" variable that the loop uses.

for( i = 0; i < source.length; i++) {
source[i].onchange = function() {
name[i].value = this.value;

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JQuery :: Related To Setting Global Variables From Anonymous Function (valid = False;)?

Oct 22, 2010

//<input type="text" id="s_field" value=""/>
var valid = true;
var div = $("#s_field");
$.post("index.php",{id: 6}, function (data){


When posting data, and getting response need to set valid to false - email is not valid.

1. in function it alerts valid is false
2. outside function it says valid is still true!

even i didn't wrote var valid = false;, but valid = false;I need to set Global "valid" variable to false.

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Accessing Class Member Using This Inside An Anonymous Function Call In A Class Method?

Mar 28, 2010

I'm using jquery to make it easy for AJAX calls.

So I create a class: function cMap(mapID){//vars and stuff}

I go and prototype a function: cMap.prototype.loadMap = function(){ //jquery AJAX call }

Now in the jquery $.ajax({...}); call, I use an anonymous function on the "success:" call: success: function(data){ this.member = data; }

My problem is that inside this anonymous function call I'm trying to call a class member of my cMap class to store the data in from the AJAX call, but it's out of scope. So the JS console in FF/Chrome throws errors about bad value/doesn't exist.

How can I access this class member from inside an anonymous function? Or at least what's a good way to go about doing all this?

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Why No Anonymous Class And Other?

Jul 7, 2007

There exists anonymous function, and you could also use a variable to contain such function. But why no class?

I mean, you could do:

$func = create_function('$a', 'print $a;');


function test($a)
print $a;
$func = 'test'
call_user_func($func, xx);

But there is no:
$class = create_class('', '');
$class = 'MyClass'
class $class {}


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Iterate Through An Anonymous Array?

Oct 11, 2009

Is it possible to iterate through an anonymous array of strings with a for loop?

Here's what I'm trying to do:
for ( i in ['country', 'city', 'state'] ) {

What I want is the string, but what I'm getting is the index number of the array, which I can't use because the array isn't named.

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Anonymous Functions In Tag Attributes?

Jun 13, 2010

I'm not having any luck writing this:

<a onclick="function(e) {clicked(e, 1);}">hit me</a>

and don't have the option of defining the click event outside the <a> tag.

Is it possible to pass in the click event and an additional parameter to the clicked function?

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RemoveEventListener With Anonymous Handler?

Jan 24, 2009

I'm writing a base class for a project and one of the class's prototypes encapsulates cross browser event listening. One point of confusion is that removeEventListener requires that you know the handler. I don't have this info because I'm creating anonymous functions, so how do I do it?Here's the code:

javascript Code:
- javascript Code


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Binding Encapsulated Anonymous Functions Without Repetition

Nov 12, 2004

Normally, if you want to bind encapsulated event listeners to an object you have to test for support and then call the same function in different ways, for example:

if(typeof document.addEventListener != 'undefined')
document.addEventListener('click', someFunction, false);
else if(document.attachEvent != 'undefined')
document.attachEvent('onclick', someFunction);

But there's code repetition there - okay not very much, because it's just a function call ... but what if you wanted to use an anonymous function ..? Well you can't - the code repetition would be unacceptible.

Except that I've though of a way :) It's really obvious actually .. but I'm posting this in the hope that others will go "wow, that's blindingly useful" as I did when I thought of it :thumbsup:

Here it is - it takes advantage of square-bracket notation to use a string reference to the supported method:

//identify supported method of adding encapsulated event listeners
etype = (typeof document.addEventListener != 'undefined') ? 'addEventListener' : (typeof document.attachEvent != 'undefined') ? 'attachEvent' : 'none'

//set event name prefix
eprefix = (etype == 'attachEvent' ? 'on' : '');

//if encapsulated event listening is not supported, don't continue
if(etype == 'none') { return; }

so anonymous functions are built like this:

element[etype](eprefix + 'event', function()
... code ...
}, false);

Even though attachEvent doesn't require a third argument, it's ignored, so this syntax works for all.

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JQuery :: Giving A Div Focus?

Oct 21, 2011

So I'm trying to build a rostering system based on - they have a free demo which I have used to get ideas and I really like the way they handle the editing of shifts - my problem is I can't figure out how to give a div focus as it were. If I could work out how to tell which div has been clicked, then get that div to listen for keypress events, I would be well on my way

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Giving Focus To Div In Mozilla

Dec 9, 2004

it seems mozilla can't focus on div? is it possible at all to focus on a div in this browser,

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Date Giving Wrong Day

Sep 19, 2011

I'm trying to make my timeclock for work, and the Date object in Javascript is giving me wrong values. I made sure that the time on my computer is the actual time, day and year, yet I either get dates that are 2 week in the future, or set in the year 2403. I have no idea what's going on, even if I just alert out a new Date() with no variables, I get the same result. If there is something that I'm not declaring or anything, I'd love to hear what it is.

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Variable Scope - Anonymous Functions And Self Invoking Closures

Jul 25, 2011

I think the last thing people seem to learn about in JavaScript when they're not coming from other programming languages is variable scope. Some even get all the way into AJAX without having learned about scope, and this is a time when it's really needed. Although the scope of JavaScript variables is non-complex by nature, it's something we should all get a full understanding for before we move too far.
Section 1: What is "scope"?
Section 2: The "var" keyword
Section 3: The "this" keyword
Section 4: Closures or "Anonymous functions and self-invoking closures

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Giving Buttons The Same Onclick Event

Oct 3, 2005

I'm mocking up an interface in javascript for an HCI assignment. I want
to be able to make the default onclick event for the buttons on my page
to display an alert since the buttons won't work yet. Is there an easy
way to do this? and it has to be as easy as giving each button their
own onclick attribute otherwise I'll just do that.

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Giving Focus To The Contents Of An IFrame

May 30, 2006

I have an intranet page which has an iframe which links to a number of
different possible .NET pages.

In one of the embedded .NET pages (and soon to be others) we want to be

able to capture keystrokes in order to link to other apps. we do this
by setting document.onkeydown to a function which handles the various

The problem I have is that when the intranet page loads with my .NET
page in its iframe, focus is not given to the .NET page, and so in
order for the page to capture keystrokes you have to click on the
contents of the iframe, which is both clunky and (it seems to me)

How do I automatically give focus to the contents of the iframe when it

loads up? I've tried putting the following script at the bottom of the
intranet page itself, but this doesn't seem to work:

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Get A Table - Giving Error That X Is Null

Feb 8, 2009

I need to get a table in javascript n i wrote this code:

But it is giving error that x is null.

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Radio Buttons Using AJAX Always Giving The Same Value

Aug 1, 2006

I am using this code using AJAX. The probelm is no matter what choice is selected I always get the result grade=5.

<li><input type="radio" id="grade" name="grade" value="5" accesskey="5">Great</li>
<li><input type="radio" id="grade" name="grade" value="4" accesskey="4">Good</li>
<li><input type="radio" id="grade" name="grade" value="3" accesskey="3">OK</li>
<li><input type="radio" id="grade" name="grade" value="2" accesskey="2">Poor</li>
<li><input type="radio" id="grade" name="grade" value="1" accesskey="1">Oh, oh</li>
<li><input type="radio" id="grade" name="grade" value="0" accesskey="0">What is this?</li>
<li><input value="Study now"


Now that a grade is entered it should be picked up by this text:

function createQueryString() {
var grade= document.getElementById("grade").value;
var queryString = "grade=" +grade;
return queryString;


function getNewTotals() {
var url = "getUpdatedSales.php";
url = url + "?dummy=" + new Date().getTime();
var queryString= createQueryString();"POST", url, true);
request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");


Why do I always get a result of grade=5?

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