IE8以下IE浏览器无window.innerHeight属性解决方法

IE8以下IE浏览器无window.innerHeight属性，用如下方法解决：

<script type="text/javascript">
function get_win_innerHeight(){
if(window.innerHeight!=undefined)
return window.innerheight;
else
return document.documentElement.clientHeight;
}
</script>