var left = 0;
var top = 0;

function showPopup(url){
	var xmlHttp;
	try
	  {
	  // Firefox, Opera 8.0+, Safari
	  xmlHttp=new XMLHttpRequest();
	  }
	catch (e)
	  {
	  // Internet Explorer
	  try
	    {
	    xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
		}
	  catch (e)
	    {
	    try
	      {
	      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
	      }
	    catch (e)
	      {
	      alert("Your browser does not support AJAX! Go get Firefox :-)");
	      return false;
	      }
	    }
	  }
	
	  xmlHttp.onreadystatechange=function()
	  {
	    if(xmlHttp.readyState==4)
	    { 
		  var response = xmlHttp.responseText;	
		  document.getElementById("popup").style.visibility = 'visible';
		  document.getElementById("popup").innerHTML = response;
		  grayOut(true);
    	}
	  }
	  xmlHttp.open("GET",url, true);
	  xmlHttp.send();
}

function hidePopup(){
	grayOut(false);
	document.getElementById("popup").style.visibility = 'hidden';	
}

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 || 31;
  var opacity = options.opacity || 40;
  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) {
	dark.onclick = hidePopup;
    // 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%';
    }
*/
    var pageWidth = getWidth();
	var pageHeight = getHeight();
    //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';
	 dark.onclick = null;
  }
}

function getWidth(){
	var x = 0;
	if (self.innerHeight){
	        x = self.innerWidth;
	}
	else if (document.documentElement && document.documentElement.clientHeight){
	        x = document.documentElement.clientWidth;
	}
	if (document.body){
		x = document.body.scrollWidth;
		if(x < document.body.clientWidth){
			x = document.body.clientWidth;
		}	
	}
	return x;
}

function getHeight(){
	var y = 0;
	if (self.innerHeight){
	        y = self.innerHeight;
	}
	else if (document.documentElement && document.documentElement.clientHeight){
	        y = document.documentElement.clientHeight;
	}
	if (document.body){
	        
			y = document.body.scrollHeight;
			if(y < document.body.clientHeight){
				y = document.body.clientHeight;
			}
	}
	return y;
}