//#########################################################################################
//# Copyright (C) 2006 StopDog, Inc. All Rights Reserved.
//# Author        : Reza Akhavan (reza@exodusweb.com)
//# Inception     : September 17, 2006
//# Contributers  : ???
//#////////////////////////////////////////////////////////////////////////////////////////
//# Change Log
//#    2008-01-14 > by Scott Wilfong
//#               >  
//#########################################################################################

function grayOut(vis, options){
	// Pass true to gray out screen, false to ungray
	// options are optional.  This is a JSON object with the following (optional) properties
	// opacity:0-100
	//		Lower number = less grayout higher = more of a blackout
	// zindex: #
	//		HTML elements with a higher zindex appear on top of the gray out
	// bgcolor: (#xxxxxx)
	//		Standard RGB Hex color code
	//
	// grayOut(true, {'zindex':'50', 'bgcolor':'#0000FF', 'opacity':'70'});
	//		Because options is JSON opacity/zindex/bgcolor are all optional and can appear
	//		in any order.  Pass only the properties you need to set.

	var options = options || {};
	var zindex = options.zindex || 50;
	var opacity = options.opacity || 30;
	var opaque = (opacity / 100);
	var bgcolor = options.bgcolor || '#000000';
	var dark=document.getElementById('darkenScreenObject');
	var scanning = document.getElementById("scanning");
	if (!dark){
		// The dark layer doesn't exist, it's never been created.  So we'll
		// create it here and apply some basic styles.
		// If you are getting errors in IE see: http://support.microsoft.com/default.aspx/kb/927917
		var tbody = document.getElementsByTagName("body")[0];
		var tnode = document.createElement('div');			// Create the layer.
		tnode.style.position='absolute';					// Position absolutely
		tnode.style.top='0px';								// In the top
		tnode.style.left='0px';								// Left corner of the page
		tnode.style.overflow='hidden';						// Try to avoid making scroll bars
		tnode.style.display='none';							// Start out Hidden
		tnode.id='darkenScreenObject';						// Name it so we can find it later
		tbody.appendChild(tnode);							// Add it to the web page
		dark=document.getElementById('darkenScreenObject');	// Get the object.
	}
	if (vis){
		// Calculate the page width and height
		var pageWidth = document.getWindowWidth() + "px";
		var pageHeight = document.getWindowHeight() + "px";
		var pageWidth = document.getDocumentWidth();
		var pageHeight = document.getDocumentHeight();

		//calculate where to display 'scanning' box
		var top = Math.round(document.getWindowHeight() / 2) + document.getScrolledY() - 100;
		var left = Math.round(document.getWindowWidth() / 2) + document.getScrolledX() - 270;

		//set the shader to cover the entire page and make it visible.
		dark.style.opacity=opaque;
		dark.style.MozOpacity=opaque;
		dark.style.filter='alpha(opacity='+opacity+')';
		dark.style.zIndex=zindex;
		dark.style.backgroundColor=bgcolor;
		dark.style.width= pageWidth;
		dark.style.height= pageHeight;
		dark.style.display='block';
		scanning.style.left = left+'px';
		scanning.style.top = top+'px';
		scanning.style.display='block';
	}
	else {
		dark.style.display='none';
		scanning.style.display='none';
	}
}