jquery.disable-double-submit.js

/**
 * jquery.disableDoubleSubmit
 *
 * @description When submit, the element will be disabled and show loading image.
 * @author      http://d.hatena.ne.jp/bannyan/
 * @license     The MIT License
 * @version     1.0
 * @link        http://gist.github.com/473424
 *
 * @usage
 *
 * $('#element').disableDoubleSubmit();
 * $('#element').disableDoubleSubmit({img_src: "/path/to/another_image", margin: "10 0"});
*/
(function() {
    jQuery.fn.disableDoubleSubmit = function(config) {
        config = jQuery.extend({
            img_src: "/image/loading.gif"
        }, config);

         // Preload image.
        (new Image).src = config.img_src;

        var target = this;
        target.after('<img src="' + config.img_src + '" />')
        target.hide();
    };  
})(jQuery);