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Use JS to implement form validation (with code)

php中世界最好的语言Original: 2018-04-17 15:14:312509browse

This time I will bring you the use of JS to implement form verification (with code). What are the precautions for using JS to implement form verification? The following is a practical case, let's take a look.

<!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>
<style type="text/css">
<!--
body,td,th {
  font-size: 12px;
  color: #000000;
}
body {
  background-color: #CCCCCC;
  margin-left: 0px;
  margin-top: 0px;
}
a {
  font-size: 12px;
  color: #666600;
}
a:link {
  text-decoration: none;
}
a:visited {
  text-decoration: none;
  color: #000099;
}
a:hover {
  text-decoration: underline;
  color: #6633FF;
}
a:active {
  text-decoration: none;
  color: #00FF00;
}
-->
</style>
  <script type="text/javascript">
    function checkusername()
    {
      var myform = document.getElementById("form1");
      var username = myform.username.value.length;
      if(username < 1||username>12)
      {
        errusername.innerHTML = "<font color=&#39;red&#39;>用户名不符合要求</font>";
        return false;
      }else{
        errusername.innerHTML = "<font color=&#39;green&#39;>用户名符合要求</font>";
        return true;
      }
    }
    function checkage()
    {
      var myform = document.getElementById("form1");
      var age = myform.age.value;
      if(age != parseInt(age))
      {
        errage.innerHTML = "<font color=&#39;red&#39;>年龄不符合要求</font>";
        return false;
      }else{
        errage.innerHTML = "<font color=&#39;green&#39;>年龄符合要求</font>";
        return true;
      }
    }
    function checkemail()
    {
      var myform = document.getElementById("form1");
      var mail=/^[A-Za-z0-9_-]+@[a-zA-Z0-9_-]+(\.[a-zA-Z0-9_-]+)+$/;
      if(!mail.test(myform.email.value))
      {  
        erremail.innerHTML = "<font color=&#39;red&#39;>email不符合要求</font>";
        return false;
      }else{
        erremail.innerHTML = "<font color=&#39;green&#39;>email符合要求</font>";
        return true;
      }
    }
    function checkform()
    {
      checkusername();checkage();checkemail();
      if(checkusername()&&checkage()&&checkemail())
      {
        return true;  
      }else{
        return false;
      }
    }
  </script>
</head>
<body alink="center">
 <form id="form1" name="form1" method="post" action="ttt.jsp" onsubmit="return checkform()">
<table width="777" border="0" cellpadding="1" cellspacing="1">
 <tr>
  <td colspan="3" ><p align="center">请输入你的注册信息</p></td>
 </tr>
 <tr>
  <td width="250" ><p align="right" >请输入你的用户名：</p></td>
  <td width="250"><p align="center">
     <input type="text" name="username" onblur="checkusername()" />  
   </p></td>
  <td><p id="errusername" align="center"></p></td>
 </tr>
 <tr>
  <td width="250"><p align="right">请输入你的年龄：</p></td>
  <td width="250"><p align="center" >
   <label>
   <input type="text" name="age" onblur="checkage()"/>
   </label>
  </p></td>
   <td><p align="center" id="errage"></p></td>
 </tr>
 <tr>
  <td width="250"><p align="right" >请输入你的EMAIL:</p></td>
  <td width="250"><p align="center" >
   <label>
   <input type="text" name="email" onblur="checkemail()" />
   </label>
  </p></td>
   <td><p align="center" id="erremail"></p></td>
 </tr>
 <tr>
  <td><p align="right">
   <label>
   <input type="submit" name="Submit" value="提交" />
   </label>
  </p></td>
   <td><p align="center">
    <label>
    <input type="reset" name="Submit2" value="重置" />
    </label>
   </p></td>
  <td><p align="center"></p></td>
 </tr>
</table>
 </form>
</body>
</html>

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

Use JS to implement form validation (with code)

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