如何使函数变量像jQuery插件一样被调用？

Question

Plugin:

(function( $ ){

  $.fn.myplugin = function( options ) {  

    var mymethod = function(){
      // I want to be able to access "this" here ('.element')

      return this; 
    };

    return this.each(function() {        
      // $('.element', this).mymethod(); <- how to do this?
    });

  };
})( jQuery );

I want to call mymethod like this:

$('.element').mymethod();

Is this possible?

Basically it needs to keep the chaining so I can further call other functions...

Answer 1

If you want to call it like a jQuery plugin you will have no way around adding it to the jQuery prototype ($.fn). But if you just want to have this reference the jQuery element of your selector you can just use apply :

(function( $ ){

  $.fn.myplugin = function( options ) {  

    var mymethod = function(){
      // I want to be able to access "this" here ('.element')

      return this; 
    };

    return this.each(function() {        
      mymethod.apply($('.element', this));
    });

  };
})( jQuery );

Answer 2

Close, you just lose the this keyword whenever there's a new function keyword. Try saving it first:

(function( $ ){

  $.fn.myplugin = function( options ) {  

    var that = this;

    var mymethod = function(_this, dotElem){
      // I want to be able to access "this" here ('.element')
        that.hide().blah()...

      return this; // this isn't needed as we are going to anyway return `this.each()`
    };

    return this.each(function() {        
        mymethod(this, $('.element' )); <- how to do this?
    });

  };
})( jQuery );

Answer 3

If you haven't already done so, I would highly recommend checking out the jQuery plugin authoring page. http://docs.jquery.com/Plugins/Authoring

The best way to call a specific method would be by going

$( '#foo' ).myPlugin( 'myMethod' );

The way you would achieve something like that would be like this, ( note: all taken from the jQuery plugin authoring site )

( function ( $ ) {

    var methods = {
        init : function( options ) {

            // Init function here

        },
        destroy : function( ) {

            // Teardown function here

        }
    };

    $.fn.myPlugin= function( method ) {

if ( methods[method] ) {
  return methods[method].apply( this, Array.prototype.slice.call( arguments, 1 ));
} else if ( typeof method === 'object' || ! method ) {
  return methods.init.apply( this, arguments );
} else {
  $.error( 'Method ' +  method + ' does not exist on jQuery.myPlugin' );
}    


};

})( jQuery );

Answer 4

Alter MyMethod so its a direct extension

$.fn.mymethod = function() {
   this.hide(); // the .element
   return this; // continue the daisy chain
}

// example usage
$(document).ready(function() {
   $("div").mymethod();
});

Updated x2 (had a typo)!

http://jsfiddle.net/MattLo/2TWMV/1/

Answer 5

Well, then you'd just do:

$.fn.mymethod = function () { ...   return this; }

jQuery will automatically pass the element it's called on as this .

But it's considered bad practice to add lots of functions this way. That's why most plugins just add one function to $.fn and take a string argument for which method to call.