How to get the root directory of web application in javascript_javascript skills

Copy code The code is as follows:

<script> <br>function getRootPath(){ <br> var strFullPath=window.document.location.href; <br>var strPath=window.document.location.pathname; <br>var pos=strFullPath.indexOf(strPath); <br>var prePath=strFullPath.substring(0, pos); <br>var postPath=strPath.substring(0,strPath.substr(1).indexOf('/') 1); <br>return(prePath postPath); <br>} <br>var webpath= getRootPath(); //webpath is the directory path variable <br></script>