js进行表单验证实例分析

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

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; 
        
       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

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

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>

效果图如下所示：

希望本文所述对大家的javascript程序设计有所帮助。