<%@page pageEncoding="utf-8" isELIgnored="false"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<br> function check(){</p> <pre><code> var reg = /^\w{6,30}$/; var name=$("#username").val(); var pwd=$("#password").val(); var flag = true; if(!reg.test(name)){ $("#username_msg").text("用户名为字母数字和下划线"); flag=false; } if(!reg.test(pwd)){ $("#password_msg").text("密码为字母数字和下划线"); flag=false; } } </script> </head> <body> <form action="CheckLogin.do" method="post"> <div id="all"> 用户名:<input type="text" name="username" id="username" onfocus="check();" /><span id="username_msg"></span><br/> 密码:&nbsp;&nbsp;<input type="password" name="password" id="password" onfocus="check();"/><span id="password_msg"></span><br/> <input type="submit" value="登陆"/><br/> </div> </form> </body> </code></pre> <p></html></p>