function greyOut(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 || 70;
	var opaque = (opacity / 100);
	var bgcolor = options.bgcolor || '#000000';
	var dark=document.getElementById('darkenScreenObject');
	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
		if( document.body && ( document.body.scrollWidth || document.body.scrollHeight ) )
		{ var pageWidth = document.body.scrollWidth+'px'; var pageHeight = document.body.scrollHeight+'px'; }
		else if( document.body.offsetWidth )
		{ var pageWidth = document.body.offsetWidth+'px'; var pageHeight = document.body.offsetHeight+'px'; }
		else { var pageWidth='100%'; var pageHeight='100%'; }
		//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';
	}
	else { dark.style.display='none';  }
}