解决方案 »

  1.   

    http://www.cnblogs.com/weiqt/articles/2013800.html
      

  2.   

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
     <head>
      <title>测试js--第一php网</title>
      <meta charset='utf-8'>
      <script language='javascript'>
      function check_me(){
      if(document.getElementById('usr').value.length>5){
         alert('wrong');
         document.getElementById("msg").innerHTML="长度不能大于5";
    }
      }
      </script>
     </head> <body>
    <form id='testform'>
    <input type='text' value='' id='usr' name='usr'><span id="msg"></span>
    <a href="javascript:check_me()">验证</a>
    </form> </body>
    </html>
      

  3.   

    function wxPhonePwd() {
                var phonePwd = $("#txtphonePwd").val();
                if (phonePwd.length == 0) {
                    $("#lblphonePwd").css({ color: "red" });
                    $("#lblphonePwd").text("请输入密码!");
                    //alert("请输入密码!");
                    return false;
                } else {
                    $("#lblphonePwd").css({ color: "green" });
                    $("#lblphonePwd").text("OK");
                    return ture;
                }
            }