function grayOut(vis, options) {
  var options = options || {}; 
  var zindex = options.zindex || 50;
  var opacity = options.opacity || 65;
  var opaque = (opacity / 100);
  var bgcolor = options.bgcolor || '#01135D';
  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) {
    // 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%';
    }   
    
    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';
  }
}