function overlayopen(divid,blackoverlayid)
  {
   var browserName = whichBrs(); 
   //var maintableHeight = document.getElementById("bg-mmt-header").offsetHeight;
   var leftPos = (screen.width / 2) - 390;
   var topPos = (screen.height / 2) - 320;
   var bodywidth;
   var bodyheight;
   
   document.getElementById(divid).style.left=leftPos+"px";
   document.getElementById(divid).style.top=topPos+"px";
      
   bodywidth = document.body.scrollWidth;
   bodyheight = document.body.scrollHeight;

   document.getElementById(blackoverlayid).style.height=bodyheight+"px";	

   if(browserName=="IE")
  	{
  	 	document.getElementById(blackoverlayid).style.width=bodywidth+"px";
  	 	document.getElementById(blackoverlayid).style.height=bodyheight+"px";	
  	}

   if(browserName=="Firefox")
  	{
  	 	document.getElementById(blackoverlayid).style.height=bodyheight+"px";	
 		document.getElementById(divid).style.top=topPos-30+"px";	  		
  	}

  	document.getElementById(divid).style.display="block";
  	document.getElementById(blackoverlayid).style.display="block";
  }	
  
  
  function overlayclose(divid,blackoverlayid)
  {
  	document.getElementById(divid).style.display="none";
  	document.getElementById(blackoverlayid).style.display="none";
  }
  
  
  
function whichBrs() {
		var agt=navigator.userAgent.toLowerCase();
		if (agt.indexOf("opera") != -1) return 'Opera';
		if (agt.indexOf("staroffice") != -1) return 'Star Office';
		if (agt.indexOf("webtv") != -1) return 'WebTV';
		if (agt.indexOf("beonex") != -1) return 'Beonex';
		if (agt.indexOf("chimera") != -1) return 'Chimera';
		if (agt.indexOf("netpositive") != -1) return 'NetPositive';
		if (agt.indexOf("phoenix") != -1) return 'Phoenix';
		if (agt.indexOf("firefox") != -1) return 'Firefox';
		if (agt.indexOf("safari") != -1) return 'Safari';
		if (agt.indexOf("skipstone") != -1) return 'SkipStone';
		if (agt.indexOf("msie") != -1) return "IE";
		if (agt.indexOf("netscape") != -1) return 'Netscape';
		if (agt.indexOf("mozilla/5.0") != -1) return 'Mozilla';
		if (agt.indexOf('\/') != -1) {
		if (agt.substr(0,agt.indexOf('\/')) != 'mozilla') {
		return navigator.userAgent.substr(0,agt.indexOf('\/'));}
		else return 'Netscape';} else if (agt.indexOf(' ') != -1)
		return navigator.userAgent.substr(0,agt.indexOf(' '));
		else return navigator.userAgent;
}