What does $($(this)) mean?

Question

I saw some code around the web that uses the following statement

if ($($(this)).hasClass(\"footer_default\")) {
      $(\'#abc\')
        .appendTo($(this))
             


        

Answer 1

As explained before me, $($(this)) and $(this) are absolutely identical. jQuery returns the same jQuery object if you try to wrap it more than once.

Additionally, for performance considerations it is a good practice to reuse jQuery objects - it is quite expensive to create jQuery objects, especially the ones with complex selectors. Example:

var $this = $(this);
if ($this.hasClass("footer_default")) {
    $('#abc')
        .appendTo($this)
        .toolbar({position: "fixed"});
}

Just google for 'jQuery best practices' - it will take a 30 min for you to learn these basics and you will use jQuery way more effectively.