Personal feeling is available, please correct me! <?php session_start(); //If you directly open the user background homepage, determine whether the stage variable is empty. If it is empty, go to the registration page. If it is not empty, go to the homepage. $sjh= $_SESSION['MM_UserNmae1']; if ($sjh !== null) { echo "

Available front-end jqyuery username and mobile phone number verification written by yourself-PHP Chinese Network Q&A

Personal feeling is available, please correct me!
<?php session_start() ; //如果直接打开用户后台首页就判断阶段变量是否为空，如果为空就来到注册页面，如果不为空就进入首页 $sjh=$ _SESSION[ 'MM_UserNmae1']; if ($sjh !==n ull) { echo "<script>top.location='index.php';</script>"; exit; }?>
  <!doctype html>
  <html>
    
    <head>
      <meta charset="utf-8">
      <title>用户登录</title>
      <link href="../css/tou.css" rel="stylesheet" type="text/css">
      <link href="../css/dibu.css" rel="stylesheet" type="text/css"></head>
    
    <body style="background-image:url(../ditu.png);background-attachment:fixed;background-color:#000;">
      <?php require_once( '../header.php'); ?>
        <table width="444" height="272" border="1" align="center" cellpadding="0" cellspacing="0" style="font-size: 20px; color: #F5F5F5;">
          <tbody>
            <tr>
              <td colspan="4" align="center" style="color: #EDEC0D">
                <strong>用 户 登 录</strong></td>
            </tr>
            <tr>
              <td width="100" align="center">
                <label for="sjh">手机：</label></td>
              <td colspan="2" align="center">
                <input name="sjh" id="sjh" type="text" style="font-size: 18px;" size="16" maxlength="11" autofocus="" oninput="value=value.replace(/[^\d]/g,'')" placeholder="11位数手机号"></td>
              <td width="132">
                <p id="s1" style="font-size: 14px;">请输入手机号</p></td>
            </tr>
            <tr>
              <td align="center">
                <label for="mima">密码：</label></td>
              <td colspan="2" align="center">
                <input name="mima" id="mima" type="text" style="font-size: 18px;" size="16" maxlength="8" onkeyup="this.value=this.value.replace(/[^\w_]/g,'');" placeholder="密码六到八位数"></td>
              <td>
                <p id="s2" style="font-size: 14px;">请输入密码</p></td>
            </tr>
            <tr>
              <td align="center">
                <label for="yzm">验证码：</label></td>
              <td width="102" align="center">
                <input name="yzm" id="yzm" type="text" style="font-size: 18px;" size="6" maxlength="4" onkeyup="this.value=this.value.replace(/[^\w_]/g,'');"></td>
              <td width="119" align="center">
                <img src="yzm.php" alt="" width="100" height="30" onClick="this.src=this.src+'?'+Math.random()" /></td>
              <td>
                <p id="s5" style="font-size: 14px;">请输入验证码</p></td>
            </tr>
            <tr>
              <td colspan="4">
                <input style="font-size: 20px; margin-left: 170px" name="submit" type="submit" value="点击登录" id="submit">
                <span id="s6" style=" font-size: 14px;"></span>
              </td>
            </tr>
          </tbody>
        </table>
        <?php require_once( '../footer.php'); ?></body>
    <script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">//失去焦点开始判断-手机号不足11位自动弹出警告且重新获取焦点	$("#sjh").blur(function(){   	var p = $('#sjh').val();	if(p.length<11){	$("#s1").text("手机号不合法").css('color', 'red');	//setTimeout("$('#sjh').focus()",1);	     $('#sjh').focus()  //不对头就移开当前焦点	               }else{$("#s1").text("符合要求").css('color', 'green');}                                });	//失去焦点开始判断-密码不足6位自动弹出警告且重新获取焦点	$("#mima").blur(function(){   	var p = $('#mima').val();	if(p.length<6){	$("#s2").text("密码不能够少于6位").css('color', 'red'); $('#mima').focus()	              }else{$("#s2").text("符合要求").css('color', 'green');}                                });	//失去焦点开始判断-确认验证码不足4位弹出提示框	$("#yzm").blur(function(){  	var q = $('#yzm').val();	if(q.length<4){	$("#s5").text("验证码需4位数").css('color', 'red');	$('#yzm').focus();	              }else{$("#s5").text("符合要求").css('color', 'green');}                                });
      </script>
    <script type="text/javascript">$(document).ready(function() {
        $("#submit").click(function() {
          var a = $('#s1').text();
          var b = $('#s2').text();
          var e = $('#s5').text();
          if (a == '符合要求' && b == '符合要求' && e == '符合要求') { //alert('符合要求');	  	  $.post("reg11.php",{	sjh:$('#sjh').val(), mima:$('#mima').val(),	yzm:$('#yzm').val(),	},	function(data){	  $("#s6").text(data).css('color', 'red');			  if($.trim(data) =='登录成功'){	  $(window).attr('location','index.php');  //成功就页面转向	  //alert("信息跳转: " + data );	                   }else{	     //alert("信息1: " + data );	             return false} }); 	  }else{alert('请填写信息再点击登录！');}     	        });});
            </script>
  
  </html>