JS how to get the project root directory

Getrootpath =function(){    //get the current URL, such as: http://localhost:8080/ems/Pages/Basic/Person.jsp    varCurwwwpath =Window.document.location.href; //gets the directory after the host address, such as:/ems/pages/basic/person.jsp    varPathName =Window.document.location.pathname; varpos =Curwwwpath.indexof (pathName); //get host address, such as: http://localhost:8080    varLocalhostpath = curwwwpath.substring (0, POS); //get the project name with "/", such as:/ems    varProjectName = pathname.substring (0, Pathname.substr (1). IndexOf ('/') + 1); returnLocalhostpath;};

JS how to get the project root directory