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>