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 || 70;
var opaque = (opacity / 100);
var bgcolor = options.bgcolor || '#000000';
var dark=document.getElementById('darkenScreenObject');

if (!dark) {
var tbody = document.getElementsByTagName("body")[0];var tnode = document.createElement('div');
tnode.style.position='absolute';tnode.style.top='0px';tnode.style.left='0px';tnode.style.overflow='hidden';
tnode.style.display='none';tnode.id='darkenScreenObject';tbody.appendChild(tnode);dark=document.getElementById('darkenScreenObject');
}

if (vis) {

	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%';
	}

	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';
	}
}