function   showDialog(url,w,h)   
{   var feature;
if(   document.all   )//IE   
{   
feature="dialogWidth:" + w + "px;dialogHeight:" + h + "px;status:no;help:no";   
window.showModalDialog(url,null,feature);   
}   
else   
{   
                                    //modelessDialog可以将modal换成dialog=yes   
feature   ="width=" + w + ",height=" + h + ",menubar=no,toolbar=no,location=no,";   
feature+="scrollbars=no,status=no,modal=yes";     
window.open(url,null,feature);   
}   
}