// JavaScript Document
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) 
	{    
		// 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';  
	}
}