难题，如何样用javascript在iframe里面写javascript脚本

难题，怎么样用javascript在iframe里面写javascript脚本
问题很简单，如
<script   language   =   javascript>
function   testWrite(){
window.myFrame.document.write( " <script   language   =   javascript> </script> ");
}
</script>

不行啊，估计要把写入的脚本转义。。。

------解决方案--------------------
<script language = javascript>
function testWrite(){
window.myFrame.
var s = document.createElement( "script ");
s.setAttribute( "language ", "javascript ");
window.myFrame.document.getElementsByTagName( "head ")[0].appendChild(s);
}
</script>