完成登录与注册页面的前端

完成登录与注册页面的HTML+CSS+JS，其中的输入项检查包括：

用户名6-12位

首字母不能是数字

只能包含字母和数字

密码6-12位

注册页两次密码是否一致

登陆

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" type="text/css" href="../static/css/aa.css">
    <script src="../static/js/aa.js"></script>


</head>
<body>
<div class="Outbox">
      <div class="box">
          <h2>欢迎来到博客园，代码改变世界！</h2>
          <h3>登录页面</h3>

        <div class="input_box">
           账号：<input id="umane"type="text"placeholder="请输入账号">
        </div>
        <div class="input_box">
           密码：<input id="upass"type="password"placeholder="请输入密码">
        </div>
          <div id="error_box"><br></div>
          <div class="input_box">
              <button onclick="myLogin()">登录</button>
               <button onclick=window.alert("请重新输入")>取消</button></div>

          </div>
</div>

</body>
</html>

function myLogin() {
            var oUname = document.getElementById("umane");
            var oError = document.getElementById("error_box");
             var oUpass = document.getElementById("upass");
            oError.innerHTML = "<br>"
     //oUname
        if (oUname.value.length>12 || oUname.value.length<6){
            oError.innerHTML = "用户名必须为6到12位数";
            return;
         } else if((oUname.value.charCodeAt(0)>=48) && oUname.value.charCodeAt(0)<=57){

            oError.innerHTML = "首字母不能为数字";
            return;
        }else for(var i=0; i<oUname.value.length;i++)
        {

     if((oUname.value.charCodeAt(i)<48 || oUname.value.charCodeAt(i)>57)&&(oUname.value.charCodeAt(i)<97 || oUname.value.charCodeAt(i)>122 )){
                    oError.innerHTML = "用户名只能包含字母和数字";
                    return;
                }
            }


            if(upass.value.length>12 || upass.value.length<6){
                oError.innerHTML="密码为6到12位数";
                return;
            }
            window.alert("已成功登陆")

        }

h3{
   align:center;
   font-family: 楷体;
   font-size: large;
   }
.Outbox{
    display: -webkit-flex;
    display: flex;
    width: 400px;
    height: 250px;
    padding-left: 100px;
    padding-top: 30px;
    background-color:greenyellow;
    }
#input_box{
    align:center;
    margin:500px;
    padding-left:500px;

    }

#error_box{
    color: orangered;
    }
body{ padding-right:500px; margin-top:100px; padding-left:500px; font-size:16px; padding-bottom:40px; padding-top:40px; font-family:verdana,Arial,Helvetica,sans-serif; }

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" type="text/css" href="aa.css">
    <script src="aa.js"></script>


</head>
<body>
<div class="Outbox">
      <div class="box">
          <h2>欢迎来到博客园，代码改变世界！</h2>
          <h3>用户注册</h3>
       <div class="input_box">
          输入账号：<input id="umane"type="text"placeholder="请输入用户名">
       </div>
        <div class="input_box">
            输入密码：<input id="upass"type="password"placeholder="请输入密码">
       </div>
          <div class="input_box">
           确认密码：<input id="userpass1" type="password" placeholder="请再次输入密码">
    </div>
          <div id="error_box"><br></div>
          <div class="input_box">
              <button onclick="myLogin()">注册</button>
<button onclick=window.alert("取消注册") type="submit" class="btn btn-primary btn-block btn-large">返回</button>

          </div>
      </div>
</div>
</body>
</html>

function myLogin(){
            var oUname = document.getElementById("umane");
            var oError = document.getElementById("error_box");
             var oUpass = document.getElementById("upass");
             var  oUpass1= document.getElementById("userpass1");
            oError.innerHTML = "<br>"
     //oUname
        if (oUname.value.length>12 || oUname.value.length<6){
            oError.innerHTML = "用户名为6到12位数";
            return;
         }
         else if((oUname.value.charCodeAt(0)>=48) && oUname.value.charCodeAt(0)<=57){

            oError.innerHTML = "首字母不能是数字";
            return;
        }
        else for(var i=0; i<oUname.value.length;i++) {

     if((oUname.value.charCodeAt(i)<48 || oUname.value.charCodeAt(i)>57)&&(oUname.value.charCodeAt(i)<97 || oUname.value.charCodeAt(i)>122 )){
                    oError.innerHTML = "只能包含字母和数字";
                    return;
                }
            }

       if(upass.value.length>12 || upass.value.length<6){
                oError.innerHTML="密码为6到12位数";
                return;
            }
            if(oUpass.value != oUpass1.value){
                oError.innerHTML="两次密码输入不一致";
                return;
            }
             window.alert("已成功注册")

        }

h3{
   align:center;
   font-family: 楷体;
   font-size: large;
   }
.Outbox{
    display: -webkit-flex;
    display: flex;
    width: 400px;
    height: 250px;
    padding-left: 100px;
    padding-top: 30px;
    background-color:greenyellow;
    }
#input_box{
    align:center;
    margin:500px;
    padding-left:500px;
    width: 100%;
    }
#error_box{
    color: orangered;
    }
body{ padding-right:500px; margin-top:100px; padding-left:500px; font-size:16px; padding-bottom:40px; padding-top:40px; font-family:verdana,Arial,Helvetica,sans-serif; }