Possible Duplicates:
Why would a javascript variable start with a dollar sign?
JQuery : What is the difference between “var test” and “var $test”
var $val = 'something'
OR
var val = 'something'
$
The $
in the variable name is only part of the name, but the convention is to use it to start variable names when the variable represents a jQuery object.
var $myHeaderDiv = $('#header');
var myHeaderDiv = document.getElementById('header');
Now later in your code, you know the $myHeaderDiv
is already a jQuery object, so you can call jQuery functions:
$myHeaderDiv.fade();
var $myHeaderDiv = jQuery(myHeaderDiv); //assign to another variable
jQuery(myHeaderDiv).fade(); //use directly
//or, as the $ is aliased to the jQuery object if you don't specify otherwise:
var $myHeaderDiv = jQuery(myHeaderDiv); //assign
$(myHeaderDiv).fade(); //use
var myHeaderDiv = $myHeaderDiv.get(0);