javascript获取web应用根目录的方法

<script>
function getRootPath(){
var strFullPath=window.document.location.href;
var strPath=window.document.location.pathname;
var pos=strFullPath.indexOf(strPath);
var prePath=strFullPath.substring(0,pos);
var postPath=strPath.substring(0,strPath.substr(1).indexOf(‘/')+1);
return(prePath+postPath);
}
var webpath=getRootPath(); //webpath就是目录路径变量
</script>