js进行表单验证实例分析

2019-11-20 13:11:08

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本文实例讲述了js进行表单验证的方法。分享给大家供大家参考。具体实现方法如下：

1. 传统的表单验证代码

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head>  
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />  
<title>表单验证</title>  
<script type="text/javascript">  
  
   function $(id) {  
       return document.getElementById(id);  
   }  
     
   function check() {  
       var email = $("email").value;  
       var password = $("password").value;  
       var repassword = $("repassword").value;  
       var name = $("name").value;  
         
       if(email == "") {  
           alert("Email值不能为空");  
           $("email").focus();  
           return false;  
       }  
         
       if(email.indexOf("@") == -1 || email.indexOf(".") == -1) {  
           alert("邮箱格式不正确,必须包含@和.");  
           $("email").focus();  
           return false;  
       }  
         
       if(password == "") {  
           alert("密码不能为空");  
           $("password").focus();  
           return false;  
       }  
         
       if(password.length < 6) {  
           alert("密码长度必须大于或者等于6");  
           $("password").focus();  
           return false;  
       }  
         
       if(repassword != password) {  
           alert("两次输入的密码不一致");  
           $("repassword").focus();  
           return false;  
       }  
         
       if(name == "") {  
           alert("姓名不能为空");  
           $("name").focus();  
           return false;  
       }  
         
       for(var i = 0; i < name.length; i++) {  
           var j = name.subString(i , i+1);  
           if(isNaN(j) == false) {  
               alert('姓名中不能包含数字');  
               $("name").focus();  
               return false;  
           }  
       }  
   }  
</script>  
</head>  
<body>  
  <form name="login_form" method="post" onsubmit="return check()">  
      <div>  
           Email:<input type="text" name="email" id="email"/>  
      </div>   
      <div>  
           密码:<input type="password" name="password" id="password" />  
      </div>  
      <div>  
          重输密码:<input type="password" name="repassword" id="repassword" />  
      </div>  
      <div>  
          姓名：<input type="text" name="name" id="name" />  
      </div>  
      <div>  
          <input type="submit" value="注册" />  
      </div>  
  </form>  
</body>  
</html>

2. 输入框后面有提示信息的表单验证

复制代码代码如下:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head>  
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />  
<title>表单验证</title>  
<script type="text/javascript">  
  
   function $(id) {  
       return document.getElementById(id);  
   }  
     
   function check() {  
       var email = $("email").value;  
       var password = $("password").value;  
       var repassword = $("repassword").value;  
       var name = $("name").value;  
           
       $("emailinfo").innerHTML = "";  
       $("passwordinfo").innerHTML = "";  
       $("repasswordinfo").innerHTML = "";  
       $("nameinfo").innerHTML = "";  
         
       if(email == "") {  
          $("emailinfo").innerHTML = "Email值不能为空";  
           $("email").focus();  
           return false;  
       }  
         
       if(email.indexOf("@") == -1 || email.indexOf(".") == -1) {  
           $("emailinfo").innerHTML = "邮箱格式不正确,必须包含@和.";  
           $("email").focus();  
           return false;  
       }  
         
       if(password == "") {  
           $("passwordinfo").innerHTML = "密码不能为空";  
           $("password").focus();  
           return false;  
       }  
         
       if(password.length < 6) {  
           $("passwordinfo").innerHTML = "密码长度必须大于或者等于6";  
           $("password").focus();  
           return false;  
       }  
         
       if(repassword != password) {  
           $("repasswordinfo").innerHTML = "两次输入的密码不一致";  
           $("repassword").focus();  
           return false;  
       }  
         
       if(name == "") {  
          $("nameinfo").innerHTML = "姓名不能为空";  
           $("name").focus();  
           return false;  
       }  
         
       for(var i = 0; i < name.length; i++) {  
           var j = name.subString(i , i+1);  
           if(isNaN(j) == false) {  
               $("nameinfo").innerHTML = '姓名中不能包含数字';  
               $("name").focus();  
               return false;  
           }  
       }  
   }  
</script>  
</head>  
<body>  
  <form name="login_form" method="post" onsubmit="return check()">  
      <div>  
           Email:<input type="text" name="email" id="email"/><span id="emailinfo"></span>  
      </div>     
      <div>  
           密码:<input type="password" name="password" id="password" /><span id="passwordinfo"></span>  
      </div>  
      <div>  
          重输密码:<input type="password" name="repassword" id="repassword" /><span id="repasswordinfo"></span>  
      </div>  
      <div>  
          姓名：<input type="text" name="name" id="name" /><span id="nameinfo"></span>  
      </div>  
      <div>  
          <input type="submit" value="注册" />  
      </div>  
  </form>  
</body>  
</html>

效果图如下所示：

3. 在输入框失去焦点时触发校验函数

复制代码代码如下:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">  
<html xmlns="http://www.w3.org/1999/xhtml">  
<head>  
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />  
<title>表单验证</title>  
<script type="text/javascript">  
   function $(id) {  
       return document.getElementById(id);  
   }  
     
   function check() {  
       var email = $("email").value;  
       var password = $("password").value;  
       var repassword = $("repassword").value;  
       var name = $("name").value;  
           
       $("emailinfo").innerHTML = "";  
       $("passwordinfo").innerHTML = "";  
       $("repasswordinfo").innerHTML = "";  
       $("nameinfo").innerHTML = "";  
         
       if(email == "") {  
          $("emailinfo").innerHTML = "Email值不能为空";  
           return false;  
       }  
         
       if(email.indexOf("@") == -1 || email.indexOf(".") == -1) {  
           $("emailinfo").innerHTML = "邮箱格式不正确,必须包含@和.";  
           return false;  
       }  
         
       if(password == "") {  
           $("passwordinfo").innerHTML = "密码不能为空";  
           return false;  
       }  
         
       if(password.length < 6) {  
           $("passwordinfo").innerHTML = "密码长度必须大于或者等于6";  
           return false;  
       }  
         
       if(repassword != password) {  
           $("repasswordinfo").innerHTML = "两次输入的密码不一致";  
           return false;  
       }  
         
       if(name == "") {  
          $("nameinfo").innerHTML = "姓名不能为空";  
           return false;  
       }  
         
       for(var i = 0; i < name.length; i++) {  
           var j = name.subString(i , i+1);  
           if(isNaN(j) == false) {  
               $("nameinfo").innerHTML = '姓名中不能包含数字';  
               return false;  
           }  
       }  
   }  
     
   function checkEmail() {  //校验Email  
       $('emailinfo').innerHTML = "";  
       var email = $('email').value;  
       if(email == "") {  
            $('emailinfo').innerHTML = "Email值不能为空";  
            return false;  
       }  
         
       if(email.indexOf('@') == -1 || email.indexOf('.') == -1) {  
            $('emailinfo').innerHTML = "Email必须包含@和.";  
            return false;  
       }  
   }  
     
   function checkPassword() {  //校验密码  
      $('passwordinfo').innerHTML = "";  
      var password = $('password').value;  
      if(password == "") {  
          $("passwordinfo").innerHTML = "密码不能为空";  
          return false;  
      }  
     
     if(password.length < 6) {  
         $("passwordinfo").innerHTML = "密码长度必须大于或者等于6";  
         return false;  
      }  
   }  
     
   function checkRepassword() { //校验重新输入的密码  
      $('repassword').innerHTML = "";  
      var repassword = $('repassword').value;  
      if(repassword != password) {  
           $("repasswordinfo").innerHTML = "两次输入的密码不一致";  
           return false;  
       }  
   }  
     
   function checkName() {  //校验姓名  
       $('nameinfo').innerHTML = "";  
       var name = $('name').value;  
       if(name == "") {  
          $("nameinfo").innerHTML = "姓名不能为空";  
           return false;  
       }  
         
       for(var i = 0; i < name.length; i++) {  
           var j = name.subString(i , i+1);  
           if(isNaN(j) == false) {  
               $("nameinfo").innerHTML = '姓名中不能包含数字';  
               return false;  
           }  
       }  
   }  
</script>  
</head>  
<body>  
  <form name="login_form" method="post" onsubmit="return check()">  
      <div>  
           Email:<input type="text" name="email" id="email" onblur="checkEmail();"/><span id="emailinfo"></span>  
      </div>     
      <div>  
           密码:<input type="password" name="password" id="password" onblur="checkPassword();"/><span id="passwordinfo"></span>  
      </div>  
      <div>  
          重输密码:<input type="password" name="repassword" id="repassword" onblur="checkRepassword();"/><span id="repasswordinfo"></span>  
      </div>  
      <div>  
          姓名：<input type="text" name="name" id="name" onblur="checkName();"/><span id="nameinfo"></span>  
      </div>  
      <div>  
          <input type="submit" value="注册" />  
      </div>  
  </form>  
</body>  
</html>