What is the difference between $ and jQuery

Question

When I try to use $(\"#div_id\") in $(document).ready it returns NULL, but when I use jQuery(\"#div_id\") it returns the actual object

Answer 1

$ is also used in Prototype.js, which is a javascript framework like jQuery. It could be the case that your project also includes references to this framework.

For more info on how the prototype dollar works, go here.

You can make the two work together with the noConflict statement, as stated in the other answers. We're doing this in one of our projects, which uses the $(element) for legacy prototype code, and jQuery(element) for new jQuery code.