jquery variable syntax [duplicate]

Question

I'm learning jQuery by trying to understand other people's code. I ran into this:

jQuery.fn.myFunc = function(options, callback) {  //stuff    jQuery(this)[settings.event](function(e) {     var self = this,     $self = jQuery( this ),     $body = jQuery( "body" );      //etc.   }  //more stuff  } 

My understanding is that $ refers to the jQuery object. So why put $ with $self and $body? And is self the same as $self?

Answer 1

$self has little to do with $, which is an alias for jQuery in this case. Some people prefer to put a dollar sign together with the variable to make a distinction between regular vars and jQuery objects.

example:

var self = 'some string'; var $self = 'another string'; 

These are declared as two different variables. It's like putting underscore before private variables.

A somewhat popular pattern is:

var foo = 'some string'; var $foo = $('.foo'); 

That way, you know $foo is a cached jQuery object later on in the code.