var title=document.createElement("h4"); 
   title.setAttribute("id","msgTitle"); 
   title.setAttribute("align","right"); 
   title.style.margin="0"; 
   title.style.padding="3px"; 
   title.style.background=bordercolor; 
 

 

 title.style.filter="progid:DXImageTransform.Microsoft.Alpha(startX=20, 

startY=20, 

finishX=100, finishY=100,style=1,opacity=75,finishOpacity=100);"; 
   title.style.opacity="0.75"; 
   title.style.border="1px solid " + bordercolor; 
   title.style.height="18px"; 
   title.style.font="12px Verdana, Geneva, Arial, Helvetica, sans-serif"; 
   title.style.color="white"; 
   title.style.cursor="pointer"; 
   title.innerHTML="关闭"; 
   title.onclick=function(){ 
          document.body.removeChild(bgObj); 
          document.getElementById("msgDiv").removeChild(title); 
          document.body.removeChild(msgObj); 
        } 
   document.body.appendChild(msgObj); 
   document.getElementById("msgDiv").appendChild(title); 
   var txt=document.createElement("p"); 
   txt.style.margin="1em 0" 
   txt.setAttribute("id","msgTxt"); 
   txt.innerHTML=str; 
   document.getElementById("msgDiv").appendChild(txt);