Many JavaScript libraries use $ as a function or variable name, just as jQuery does. In jQuery’s case, $ is just an alias for jQuery, so all functionality is available without using $. If we need to use another JavaScript library alongside jQuery, we can return control of $ back to the other library with a call to $.noConflict():
Creates a different alias instead of jQuery to use in the rest of the script.
var $j = jQuery.noConflict(); // Do something with jQuery $j("div p").hide(); // Do something with another library's $() $("content").style.display = 'none';