jquery-plugin-how-to-create-a-plugin.rst

jQuery Plugin How to Create a Plugin

Reference: http://learn.jquery.com/plugins/ ( recommended! )

Protecting the $ Alias and Adding Scope

Note

The $ variable is very popular among JavaScript libraries, and if you're using another library with jQuery, you will have to make jQuery not use the $ with jQuery.noConflict(). However, this will break our plugin since it is written with the assumption that $ is an alias to the jQuery function. To work well with other plugins, and still use the jQuery $ alias, we need to put all of our code inside of an Immediately Invoked Function Expression, and then pass the function jQuery, and name the parameter $:

(function ( $ ) {
        $.fn.greenify = function() {
                this.css( "color", "green" );
                return this;
        };

        $.ltrim = function( str ) {
                return str.replace( /^\s+/, "" );
        };

        $.rtrim = function( str ) {
                return str.replace( /\s+$/, "" );
        };
}( jQuery ));

In addition, the primary purpose of an Immediately Invoked Function is to allow us to have our own private variables. Pretend we want a different color green, and we want to store it in a variable.

(function ( $ ) {
        var shade = "#556b2f";
        $.fn.greenify = function() {
                this.css( "color", shade );
                return this;
        };
}( jQuery ));