jQuery: Accessing the Checked Value of an ASP.net CheckBox Control

You can access the checked value of an ASP.net generated checkbox by doing the following.

    function ShowWarning() {
        var checkboxList = $("#");
        var myCheckbox = checkboxList[0];
        if (myCheckbox.checked) {

JQuery: Error: jQuery.support is undefined

jQuery.support is undefined

if ( !jQuery.support.opacity && name == “opacity” ) {

If you are getting this error when trying to use JQuery.hide or JQuery.show it is most likely because you are also using the JQuery VisualStudio Intellisense Documentation ( VSDOC ). The error is simply caused by the fact that you are loading the VSDOC after JQuery. JavaScript loads/renders in the order you have it on the page and by loading the documentation after you load JQuery you are loading things out of order. Simply make sure you load the VSDOC first then JQuery and you are good to go.

JQuery: Getting Pretty Much Everything in the DOM

$('div:hidden') gets all 'div' elements which have their 'display' style attribute set to 'hidden'

$('li:eq(0)') gets the first item in the list

$('li:lt(3)') gets the first 3 items in the list (0 based)

$('li:even') gets all list items with a even index (0 based)

$('li:not(.some)') gets the lost items which do not have the css class ‘some’

$('p, li.some') gets all 'p' elements as well as all 'li' elements with a css class of 'some'

$('li .some> p') gets all 'p' elements which are children of any element with a css class of 'some' which are in turn children of a 'li' element

$('p a[@href*=http]') gets all ‘a’ elements which are children of a ‘p’ element that have a ‘http’ within the ‘href’ attribute

$('li + li > a[@href$=zip]') gets all 'a' elements which have 'zip' in the 'href' attribute which are children of a 'li' element which is in turn the child of another 'li' element

Full List of DOM Traversing Functions

JQuery: Chainable If-Else Statement

To add chainable if-else statements to your JQuery library add the following to your standard include file.

Single If-Else: calls a single function if true

jQuery.fn.sif = function(state, trueFunc) { if (state) { trueFunc; }

Double If-Else: with 2 potential function calls, one if true, the other if false.

jQuery.fn.dif = function(state, trueFunc, falseFunc) { if (state) { trueFunc; } else { falseFunc; }

JQuery: Checking if Element Exists in DOM

Easiest and quickest way to check if an element exists in the DOM before attempting to manipulate it is to simply check the length attribute of the find method.

$(‘SomeElement’).length == 0; // if 0 element does not exist

In order to make it a chainable check you can simply add a wrapper method to your JQuery include file.

jQuery.fn.IfExists = function() { if(this.length > 0) return this; };