iframe 自适应高度、宽度

示例：

 <iframe id="zyms" frameborder="0" scrolling="yes" style="1000px;" 
onload=" this.height = 0;var fdh = (this.Document ? this.Document.body.scrollHeight : this.contentDocument.body.offsetHeight);
this.height = (fdh > 600 ? fdh : 600);">
 </iframe>