Question

Are these three equivalent?

$(function(){
  $("#a").html("i am a")
});

(function($){
  $("#b").html("i am b")
})($);

(function(){
  $("#c").html("i am c")
})(); 

The code is available here.

Reference:

• jQuery document ready functions

Answer 1

The first one actually waits for the ready event, while the others do not.

The second one is used for aliasing JQuery, but is useless in the way it is used now. You pass $, which is received in the parameter $. This construct is usually used when another library is used that assigns a different value to $. In that case you can call function($){...}(jQuery), to still have the $ variable pointing to jQuery in the scope of the function.