需要当用户登录出错时给出提示，请问我该怎么设计？

Question

window["lib"]["lognModule"] = (function () {
var uniqueLogn;
function constructor() {
var lognHtml = "<div id='light'>";
lognHtml = lognHtml + "<div id='tabsHead'><a class='curtab' id='tabs1' href='javascript:showTab(\"tabs1\",\"tabContent1\")'>登陆</a>";
lognHtml = lognHtml + "<a class='tabs' id='tabs2' href='javascript:showTab(\"tabs2\",\"tabContent2\")'>注册</a>";
lognHtml = lognHtml + "<a style='float:right;' href='javascript:cancle()' onclick=''>X</a>";
lognHtml = lognHtml + "</div><div id='tabContent1' style='display:block;background-color: white;'>";
lognHtml = lognHtml + "<table style='hight:270px;backgroud:white;'><tr><td>Username:</td><td><input id='UsernameID' type='text' /></td></tr>";
lognHtml = lognHtml + "<tr><td>Password:</td><td><input id='PasswordID' type='password'/></td></tr>";
lognHtml = lognHtml + "";
lognHtml = lognHtml + "<tr><td colspan='2' align='center'><input onclick='logIn()' value='OK' type='button' /></td></tr>";
lognHtml = lognHtml + "</table></div><div id='tabContent2' style='display:none;'><iframe id='registerIframe' style='background-color:white;' height='270px' frameborder='0' scrolling='no' src='register.htm'></iframe></div></div>";
return lognHtml;

function ResponseForLogIn(ResTxt) {
var tmp = getValueFromContent(ResTxt, "result");
switch (tmp) {
case "nouser":
$("waitSecondID").style.display = "";
if (Sys.ie) {
second = $("totalSecond").innerText;
}
else {
second = $("totalSecond").textContent;
}
setInterval(function () {
redirect(url, second);
second--;
}, 1000);
break;
case "verified":
var temp = getValueFromContent(ResTxt, "data");
g_AllData = eval('(' + temp + ')');
createWebTable();
hideTab($('light'));
minimize($('fade'));
SetCookie("username", g_AllData.page.Muser.Us, 30, "/", true);
setUserInfo();
break;
case "incorrect username or password.":
var a = 0;
break;
}
}

谢谢！

• 
  

Answer 1

在文本框的后面放一个span给它加一个ID然后用js 的document.getElementByID("id名");获取此spanvar d=document.getElementById('id名');然后设置出错信息 d.setInnerHTML="用户名错误";即可！！

Answer 2

<div id="msg"></div>function login(){var msg=document.getElementById("msg");msg.innerHTML="用户名错误！";}

Answer 3

alert("密码错误")