jQuery plugin for links to open in a popup (built for share links)

SharePopup.js

// the semi-colon before function invocation is a safety net against concatenated
// scripts and/or other plugins which may not be closed properly.
;(function ( $, window, document, undefined ) {

    // undefined is used here as the undefined global variable in ECMAScript 3 is
    // mutable (ie. it can be changed by someone else). undefined isn't really being
    // passed in so we can ensure the value of it is truly undefined. In ES5, undefined
    // can no longer be modified.

    // window and document are passed through as local variable rather than global
    // as this (slightly) quickens the resolution process and can be more efficiently
    // minified (especially when both are regularly referenced in your plugin).

    // Create the defaults once
    var pluginName = "socialPopup",
        defaults = {
            width: 500,   // Defines the width of the popup
            height: 300,  // Defines the height if the popup
            top: 'auto',  // Defines the top position of the window (use auto for a centered window)
            left: 'auto', // Defines the left position of the window (use auto for a centered window)
            windowTitle: 'SocialPopup' // Defines the window title
        };
    var _this;

    // The actual plugin constructor
    function Plugin ( element, options ) {
        _this = this;
        _this.element = element;
        // jQuery has an extend method which merges the contents of two or
        // more objects, storing the result in the first object. The first object
        // is generally empty as we don't want to alter the default options for
        // future instances of the plugin
        _this.settings = $.extend( {}, defaults, options );
        _this._defaults = defaults;
        _this._name = pluginName;
        _this.init();
    }

    Plugin.prototype = {
        init: function () {
            // You already have access to the DOM element and
            // the options via the instance, e.g. this.element
            // and this.settings
            // you can add more functions like the one below and
            // call them like so: this.yourOtherFunction(this.element, this.settings).
            $(_this.element).bind('click', _this.openPopup);
        },
        openPopup: function (event) {
            event.preventDefault();

            var href = this.getAttribute('href'),
                windowLeft = _this.settings.left == 'auto' ?  left = (screen.width/2)-(_this.settings.width/2) : _this.settings.left,
                windowTop = _this.settings.top == 'auto' ? (screen.height/2)-(_this.settings.height/2) : _this.settings.top;

            var popupWindow = window.open(
                href,
                _this.settings.windowTitle,
                "width="+ _this.settings.width +","+
                    "height="+ _this.settings.height +","+
                    "resizable=yes,"+
                    "menubar=no,"+
                    "status=no,"+
                    "toolbar=no,"+
                    "dependent=yes,"+
                    "location=no,"+
                    "left=" + windowLeft +","+
                    "top=" + windowTop
            );
            popupWindow.focus();
        }
    };

    // A really lightweight plugin wrapper around the constructor,
    // preventing against multiple instantiations
    $.fn[ pluginName ] = function ( options ) {
        return this.each(function() {
            if ( !$.data( this, "plugin_" + pluginName ) ) {
                $.data( this, "plugin_" + pluginName, new Plugin( this, options ) );
            }
        });
    };

})( jQuery, window, document );

SharePopup.min.js

!function(a,b){function h(b,c){g=this,g.element=b,g.settings=a.extend({},f,c),g._defaults=f,g._name=e,g.init()}var g,e="socialPopup",f={width:500,height:300,top:"auto",left:"auto",windowTitle:"SocialPopup"};h.prototype={init:function(){a(g.element).bind("click",g.openPopup)},openPopup:function(a){a.preventDefault();var c=this.getAttribute("href"),d="auto"==g.settings.left?left=screen.width/2-g.settings.width/2:g.settings.left,e="auto"==g.settings.top?screen.height/2-g.settings.height/2:g.settings.top,f=b.open(c,g.settings.windowTitle,"width="+g.settings.width+","+"height="+g.settings.height+","+"resizable=yes,"+"menubar=no,"+"status=no,"+"toolbar=no,"+"dependent=yes,"+"location=no,"+"left="+d+","+"top="+e);f.focus()}},a.fn[e]=function(b){return this.each(function(){a.data(this,"plugin_"+e)||a.data(this,"plugin_"+e,new h(this,b))})}}(jQuery,window,document);