getRootPath = function(){

    //获取当前网址，如： http://localhost:8080/ems/Pages/Basic/Person.jsp

    var curWwwPath = window.document.location.href;

    //获取主机地址之后的目录，如： /ems/Pages/Basic/Person.jsp

    var pathName = window.document.location.pathname;

    var pos = curWwwPath.indexOf(pathName);

    //获取主机地址，如： http://localhost:8080

    var localhostPath = curWwwPath.substring(0, pos);

    //获取带"/"的项目名，如：/ems

    var projectName = pathName.substring(0, pathName.substr(1).indexOf('/') + 1);

    return localhostPath;

};