jQuery: Change plugin option after called

I've a plugin made by my own to set up a few things when using dialog of jquery-ui. Instead of calling:

$("#popup").dialog(options);

I use this:

$("#popup").dialogPlugin(options);

And dialogPlugin will call .dialog(options) (after doing some stuff).

In my plugin I may modify some functions for the events of the dialog like this:

var originalCloseFn = options.close;
options.close = function() {
    //my own stuff.
    originalCloseFn();
};

The plugin works great, but after some time using it I realized that I couldn't change the dialog functions from outside the plugin like this:

$("#popup").dialog("option", "close", newFunctionOnClose);

If I do that the code the plugin added to the close function would be lost.

So I added this code at the beggining of my plugin:

if (options == "option") {
    if (val == undefined)
        return _this.dialog("option", name);
    else
        return _this.dialog("option", name, val);
}

Now I need to change the fifth line of this code to actually change the option of my plugin, not of the jquery-ui. (The option of .dialogPlugin function, not of .dialog). I realy don't know how can I do that. Any ideas please?

Edit

I know that the question is not very clear and my poor english doesn't let me to explain myself any more s开发者_如何转开发o I've made a litle example.

What I want is that in the seventh line (return $(this).dialog("option", name, val);) instead of modifing that (equivalent to optionsForJQuery.close) modify options.close. That way I will avoid loding the plugins behavior.

try this:

HTML:

<div id="popup">I'm a popup</div>

JS:

(function ($) {
    $.fn.dialogPlugin = function (options, name, val) {

        var
            // setter function close
            fnClose = null,

            // function when close
            fnMyClose = function() {
                alert("This is plugin's close behavior");
                if (fnClose)
                    fnClose();
            };

        if (options == "option") {
            if (name == "close" && $.isFunction(val)) {
                fnClose = val;
                val = fnMyClose;
            }
        } 
        else {
            if (options.close)
                fnClose = options.close;

            options.close = fnMyClose;
        }

        return (name)
            ? $(this).dialog(options, name, val) //if var == 'undefined'is equal to not send parameters
            : $(this).dialog(options);
    };

})(jQuery);


$("#popup").dialogPlugin({
    close: function() {
        alert("This is user's first close behavior");
    }
});


$("#popup").dialogPlugin("option", "close", function() {
    alert("This is user's second close behavior");
});

EDIT

or more simple and elegant:

(function($){

    var dialog_close = $.ui.dialog.prototype.close;

    $.ui.dialog.prototype.close = function() {

        var self = this;

        alert("This is plugin's close behavior");

        dialog_close.apply(this, arguments);


    };

})(jQuery);