How to use PHP to prevent repeated submission of forms-PHP Tutorial-php.cn

How to use PHP to prevent repeated submission of forms

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Release： 2023-03-28 09:32:02

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This time I will show you how to use PHP to prevent repeated submission of forms, and what are the precautions for using PHP to prevent repeated submission of forms. The following is a practical case, let's take a look.

The code is very simple

I believe you are very smart and share a small demo with you, you can learn from it:

Specific code:

<?php
/*
* 2016年9月29日08:09:13
*/
session_start();
header("Content-Type: text/html;charset=utf-8");
function set_token() {
  $_SESSION[&#39;token&#39;] = md5(microtime(true));
}
function valid_token() {
  $return = $_REQUEST[&#39;token&#39;] === $_SESSION[&#39;token&#39;] ? true : false;
  set_token();
  return $return;
}
//如果token为空则生成一个token
if(!isset($_SESSION[&#39;token&#39;]) || $_SESSION[&#39;token&#39;]==&#39;&#39;) {
  set_token();
}
if(isset($_POST[&#39;web&#39;])){
  if(!valid_token()){
    echo "token error，请不要重复提交！";
  }else{
    echo &#39;成功提交，Value:&#39;.$_POST[&#39;web&#39;];
  }
}else{
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<title>PHP防止重复提交表单</title>
<meta name="keywords" content="PHP" />
<meta name="description" content="PHP防止重复提交表单" />
</head>
<body>
<p id="main">
  <p class="demo">
    <form method="post" action="">
      <input type="hidden" name="token" value="<?php echo $_SESSION[&#39;token&#39;]?>">
      <input type="text" class="input" name="web" value="脚本之家">
      <input type="submit" class="btn" value="提交" />
    </form>
  </p>
</p>
</body>
</html>
<?php }?>

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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!