divHtml = divHtml + "<iframe src='about:blank' style='position:absolute;top:0px;left:0px; visibility:inherit;  width:190px;height:232px;z-index:-1; scrolling='no' frameborder='0' filter='progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)';'></iframe>"
  

document.all.myDiv.innerHTML = divHtml;

这种方式有个问题，就是width和height写死了，

如果div自身设置了width和height，可以将iframe的width,height设置成100％

divHtml = divHtml + "<iframe src='about:blank' style='position:absolute;top:0px;left:0px; visibility:inherit;  width:100%;height:100%;z-index:-1; scrolling='no' frameborder='0' filter='progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)';'></iframe>"