function getRootPath() {
　　//http://10.10.20.159:90/pingtai/
　　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 + "/");
}