Question

I felt very confused about “this” keyword in jquery 1.7.3 source.some snippets showing below:

jQuery.fn = jQuery.prototype = {
constructor: jQuery,
init: function( selector, context, rootjQuery ) {
    var match, elem, ret, doc;

    // Handle $(""), $(null), or $(undefined)
    if ( !selector ) {
        return this;   
    }

    // Handle $(DOMElement)
    if ( selector.nodeType ) {
        this.context = this[0] = selector;
        this.length = 1;
        return this;
    }

---

if ( !selector ) {

  return this;   //why not only one "return" here?
                 //And does "this" refer to jQuery object?
                 //OTOH, this question is about why it returns "this".
}

Answer 1

return this allow for chainable plugin call,

$(whatever).plugin1().plugin2() etc

if you don’t return this in a plugin you won’t be able to chain it
& chaining is fast, & chaining is cool
you want to chain as much as possible in your jquery code

to answer your comment : no you do (inside plugin definition):

if ($("#div1").get(0)) {
   //do whatever to $("#div1")
   }
return this;

return this comes at the end of plugin definition no need to return it upon any condition whatsoever