if(!acPU) {
  var acPU; // static instance of the modal object that controls what's on the screen

  if(parent && parent.acPU) {
    acPU = parent.acPU; // if we're in an iframe, we want the parent instance
  } else {
    var acModalPopup = function() {
      this._variableName  = "acPU";
      this._currentIndex  = 0;
      this._previousIndex = null;
      this._isShown       = false;
      this._modals        = new Array();
      this._moveModalInfo = null;
      this._isDragging    = false;
      this._bodyOverflow  = null;

      this._modalMaskCssClass     = "ac-modal-mask";
      this._modalCssClass         = "ac-modal";
      this._modalTitleCssClass    = "ac-modal-title";
      this._modalCloseCssClass    = "ac-modal-close";
      this._modalIframeCssClass   = "ac-modal-iframe";
      this._modalContentCssClass  = "ac-modal-content";
      this._modalLoaderCssClass   = "ac-modal-loader";

      this._defaults = {
        width   : 800,
        height  : 600,
        zIndex  : 200000,
        title   : null,
        onClose : null
      };
    };
    acModalPopup.prototype = {
    	// Provided for backwards compatibility
    	Open: function (url, width, height, onCloseFunction) {
    		this.open(url, { width: width, height: height, onClose: onCloseFunction });
    	},

    	open: function (url, settings) {
    		var pu = this,
            options = $.extend(pu._defaults, settings, {});

    		pu.init(options);

    		var m = pu._modals[pu._currentIndex],
            $titleSpan = m.modalTitle.children("span"),
            titleText = "Popup Window";

    		// Set the popup title after loading the iframe
    		m.modalIframe.unbind("load.acPU").bind("load.acPU", { m: m, options: options }, pu._frameLoaded);

    		if (pu._currentIndex > 0) {
    			var $otherModals = $("." + pu._modalCssClass).not(m.modal);
    			$otherModals.css({
    				opacity: "0.4",
    				filter: "alpha(opacity=40)"
    			});
    			$otherModals.find("." + pu._modalTitleCssClass).unbind("mousedown.acPU");
    		}

    		if (pu._previousIndex == null || pu._previousIndex < 0) {
    			pu._bodyOverflow = $("body").css("overflow");
    		}

    		$("body").css("overflow", "hidden");

    		var windowWidth = $(window).width(),
            windowHeight = $(window).height(),
            scrollX = $(window).scrollLeft(),
            scrollY = $(window).scrollTop(),
    		// IE didn't support scrollX and scrollY so use JQuery
    		//scrollX = window.scrollX,
    		//scrollY = window.scrollY,
            modalDimensions = pu._calculateDimensions(m, options, windowWidth, windowHeight, scrollX, scrollY);

    		m.modalLoader.css({
    			left: modalDimensions.width / 2 - m.modalLoader.width() / 2,
    			top: modalDimensions.height / 2 - m.modalLoader.height() / 2
    		});
    		m.modalIframe.attr("src", url);

    		m.modal.css({
    			width: modalDimensions.width,
    			height: modalDimensions.height,
    			top: modalDimensions.y,
    			left: modalDimensions.x
    		}).show();
    		m.modalMask.css({
    			top: scrollY,
    			left: scrollX,
    			width: windowWidth,
    			height: windowHeight
    		}).show();

    		pu._previousIndex = pu._currentIndex;
    		pu._currentIndex = pu._currentIndex + 1;

    		pu._isShown = true;
    	},

    	// Provided for backwards compatibility
    	Close: function (returnValue) {
    		this.close(returnValue);
    	},

    	close: function (returnValue) {
    		var pu = this;
    		if (pu._isShown) {
    			var m = pu._modals[pu._previousIndex],
              $modal = m.modal,
              $modalMask = m.modalMask,
              onCloseCallback = m.onClose;

    			pu._modals[pu._previousIndex] = null;

    			pu._currentIndex = pu._previousIndex;
    			pu._previousIndex = pu._previousIndex - 1;

    			$modal.remove();

    			if (pu._previousIndex < 0) {
    				$modalMask.remove();

    				$("body").css("overflow", pu._bodyOverflow);
    				//$("body").css("overflow", "");
    				$(window).unbind(".acPU");

    				pu._bodyOverflow = null;
    				pu._previousIndex = null;
    				pu._isShown = false;
    			} else {
    				m = pu._modals[pu._previousIndex];
    				m.modal.css({
    					opacity: "1.0",
    					filter: "alpha(opacity=100)"
    				});
    				m.modalTitle.bind("mousedown.acPU", { pu: pu, index: pu._previousIndex }, pu._dragStart);
    			}

    			if (onCloseCallback) {
    				onCloseCallback(returnValue);
    			}
    		}
    	},

    	resize: function (event) {
    		var pu = event.data.pu,
            index = event.data.index,
            options = event.data.options,
            m = pu._modals[index],
            windowHeight = $(window).height(),
            windowWidth = $(window).width(),
            scrollX = window.scrollX,
            scrollY = window.scrollY,
            dimensions = pu._calculateDimensions(m, options, windowWidth, windowHeight, scrollX, scrollY);

    		m.modal.css({
    			width: dimensions.width,
    			height: dimensions.height,
    			top: dimensions.y,
    			left: dimensions.x
    		});
    	},

    	scroll: function (event) {
    		var pu = event.data.pu;
    		pu.resize(event);
    	},

    	init: function (options) {
    		var pu = this;

    		var $modalMask = $("#dvModalMask");
    		if ($modalMask.length == 0) {
    			$modalMask = $("<div />").attr("id", "dvModalMask").addClass(pu._modalMaskCssClass);
    			$modalMask.css({
    				width: "auto",
    				height: "auto",
    				position: "absolute",
    				display: "none",
    				overflow: "hidden",
    				zIndex: options.zIndex
    			});
    			$modalMask.appendTo("body");
    		}

    		var $modal = $("<div />").addClass(pu._modalCssClass);
    		$modal.css({
    			width: "auto",
    			height: "auto",
    			position: "absolute",
    			display: "none",
    			zIndex: options.zIndex
    		});
    		pu._disableSelection($modal);

    		var commonEventArgs = {
    			pu: pu,
    			index: pu._currentIndex
    		};

    		var $title = $("<div />").addClass(pu._modalTitleCssClass).css("display", "none");
    		$title.bind("mousedown.acPU", commonEventArgs, pu._dragStart);
    		pu._disableSelection($title);
    		$title.appendTo($modal);

    		var $close = $("<div />").addClass(pu._modalCloseCssClass);
    		$close.bind("click.acPU", commonEventArgs, function () {
    			pu.close();
    		});
    		$close.appendTo($title);

    		var $titleSpan = $("<span />");
    		pu._disableSelection($titleSpan);
    		$title.append($titleSpan);

    		var $loader = $("<div />").addClass(pu._modalLoaderCssClass);
    		$loader.css("position", "absolute");
    		$loader.appendTo($modal);

    		var $content = $("<div />").addClass(pu._modalContentCssClass);
    		$content.css("display", "none");
    		$content.appendTo($modal);

    		var $iframe = $("<iframe />").addClass(pu._modalIframeCssClass);
    		$iframe.css({
    			width: "100%",
    			border: "0 none"
    		}).attr("frameborder", "no");
    		$iframe.appendTo($content);

    		commonEventArgs.options = options;
    		$modal.appendTo("body");

    		$(window).bind("resize.acPU", commonEventArgs, pu.resize);
    		$(window).bind("scroll.acPU", commonEventArgs, pu.scroll);

    		pu._modals[pu._currentIndex] = {
    			modal: $modal,
    			modalTitle: $title,
    			modalClose: $close,
    			modalMask: $modalMask,
    			modalIframe: $iframe,
    			modalContent: $content,
    			modalLoader: $loader,
    			onClose: options.onClose
    		};
    	},

    	_calculateDimensions: function (m, options, ww, wh, sx, sy) {
    		var modalHeight = options.height,
            modalWidth = options.width,
            closeHeight = m.modalClose.height(),
            closeWidth = m.modalClose.width();

    		if (modalWidth + closeWidth > ww) {
    			modalWidth = ww - closeWidth;
    		}
    		if (modalHeight + closeHeight > wh) {
    			modalHeight = wh - closeHeight;
    		}

    		if (!sx) {
    			sx = 0;
    		}
    		if (!sy) {
    			sy = 0;
    		}

    		var x = (ww / 2 - modalWidth / 2) + sx,
            y = (wh / 2 - modalHeight / 2) + sy,
            result = {
            	width: modalWidth,
            	height: modalHeight,
            	x: x,
            	y: y
            };

    		return result;
    	},

    	_frameLoaded: function (event) {
    		var m = event.data.m,
            options = event.data.options,
            $titleSpan = m.modalTitle.children("span"),
            titleText = "AmeriCommerce Popup";

    		m.modalLoader.css("display", "none");
    		m.modalContent.css("display", "block");

    		try {
    			var frameTitle = m.modalIframe.contents().find("title").html();
    			if (frameTitle.length > 0) {
    				titleText = frameTitle;
    			}
    		} catch (e) {
    			// will fail if a different domain
    		}

    		if (options.title) {
    			titleText = options.title;
    		}
    		$titleSpan.html(titleText);
    		m.modalTitle.css("display", "block");
    	},

    	_dragStart: function (event) {
    		var pu = event.data.pu,
            index = event.data.index,
            m = pu._modals[index];

    		pu._moveModalInfo = {
    			startMouseX: event.pageX,
    			startMouseY: event.pageY,
    			startModalX: parseInt(m.modal.css("left").replace("px", "")),
    			startModalY: parseInt(m.modal.css("top").replace("px", ""))
    		};

    		$(document).bind("mouseup.acPU", event.data, pu._dragEnd);
    		$(document).bind("mousemove.acPU", event.data, pu._dragMove);

    		m.modalIframe.css({ display: "none" });
    		pu._isDragging = true;
    	},

    	_dragMove: function (event) {
    		var pu = event.data.pu,
            index = event.data.index,
            m = pu._modals[index],
            eventX = event.pageX,
            eventY = event.pageY,
            changeX = eventX - pu._moveModalInfo.startMouseX,
            changeY = eventY - pu._moveModalInfo.startMouseY;

    		m.modal.css({
    			left: pu._moveModalInfo.startModalX + changeX,
    			top: pu._moveModalInfo.startModalY + changeY
    		});
    	},

    	_dragEnd: function (event) {
    		var pu = event.data.pu,
            index = event.data.index,
            m = pu._modals[index];

    		pu._isDragging = false;
    		pu._moveModalInfo = null;
    		$(document).unbind("mouseup.acPU").unbind("mousemove.acPU");
    		m.modalIframe.css({ display: "block" });
    	},

    	_disableSelection: function (element) {
    		element.attr("unselectable", "on").css("MozUserSelect", "none").bind("selectstart.acPU", function () { return false; });
    	}
    };

    acPU = new acModalPopup();
  }
}