JavaScript: getRootWebSitePath

gistfile1.js

function getRootWebSitePath() {
    var _location = document.location.toString();
    var applicationNameIndex = _location.indexOf('/', _location.indexOf('://') + 3);
    var applicationName = _location.substring(0, applicationNameIndex) + '/';
    var webFolderIndex = _location.indexOf('/', _
    location.indexOf(applicationName) + applicationName.length);
    var webFolderFullPath = _location.substring(0, webFolderIndex);
 
    return webFolderFullPath;
}