(jsp语言)登录实例(JS聚集回车键,并通过Ajax判断用户名,密码的正确性)
下面是一个简单的登录实例(JS聚集回车键,并通过Ajax判断用户名,密码的正确性)

//jsp页面function checkManageLogin(){var XMLHttp;    XMLHttp = createXMLHttpRequest();    ajaxUrl = "<%=path%>/userAction.do?act=login&name="+document.forms[0].loginname.value+"&password="+document.forms[0].password.value;    XMLHttp.open("post",ajaxUrl,false);    XMLHttp.send(null);    count = XMLHttp.responseText ;    XMLHttp.abort();    if(count == 2){    alert("Password is wrong!");    document.forms[0].password.select();        return false;    }else{    if(count == 3){       alert("Username is not exsit!");       document.forms[0].loginname.select();       return false;    }else{       document.forms[0].action="<%=path%>/backend/frame.jsp";       document.forms[0].submit();       return true;    }    }}function createXMLHttpRequest() {   try{    this.XMLHttp=new XMLHttpRequest();   }catch(trymicrosoft){    try{     this.XMLHttp=new ActiveXObject("Msxml2.XMLHTTP");        }catch (othermicrosoft) {     try{      this.XMLHttp= ActiveXObject("Microsoft.XMLHTTP");     }catch (failed) {      this.XMLHttp=null;     }    }   }   return this.XMLHttp;}</script><script language="javascript">     function isKeyTrigger(e,keyCode){       var argv = isKeyTrigger.arguments;       var argc = isKeyTrigger.arguments.length;       var bCtrl = false;       if(argc > 2){           bCtrl = argv[2];       }       var bAlt = false;       if(argc > 3){           bAlt = argv[3];       }       var nav4 = window.Event ? true : false;       if(typeof e == 'undefined') {           e = event;       }       if(bCtrl &&           !((typeof e.ctrlKey != 'undefined') ?            e.ctrlKey :           e.modifiers & Event.CONTROL_MASK > 0)) {           return false;       }       if( bAlt &&           !((typeof e.altKey != 'undefined') ?                e.altKey : e.modifiers & Event.ALT_MASK > 0)){           return false;       }       var whichCode = 0;       if (nav4)    whichCode = e.which;    else if (e.type == "keypress" || e.type == "keydown") whichCode = e.keyCode;       else whichCode = e.button;       return (whichCode == keyCode);   }     function ctrlEnter(e){  // var ie = navigator.appName == "Microsoft Internet Explorer" ? true : false; //(可以判断是什么浏览器)      if(isKeyTrigger(e,13)){         checkManageLogin();         }}     </script>  //下面是个Java语言方法,一般写在action中public ActionForward login(ActionMapping mapping, ActionForm form,    HttpServletRequest request, HttpServletResponse response) {   try {    int flag = 0;    String username = request.getParameter("name");    String password = request.getParameter("password");    List<GsaUser> userList = userDao.getFrameList("from "      + GsaUser.class.getName()      + " as user where user.usertype is null and user.flag=0");    for (GsaUser saoUser : userList) {     if ((saoUser.getLoginname()).equals(username)       || (saoUser.getLoginname()) == username) {      if (password.equals(saoUser.getPassword())) {       HttpSession session = request.getSession();       session.setAttribute("managerId", saoUser.getUserid());       session.setAttribute("managerName", saoUser         .getLoginname());       flag = 1;       response.getWriter().println(flag);       return null;      } else {       flag = 2;       response.getWriter().println(flag);       return null;      }     }    }    flag = 3;    response.getWriter().println(flag);    return null;   } catch (Exception ex) {    log.error("UserAction login error...." + ex.getMessage(), ex);    return mapping.findForward("userError");   }}