Discuss the prevention rules for repeated submission of PHP forms_PHP Tutorial

When the user clicks the "Submit" button, the button will become gray and unavailable.

In the above example, the OnClick event is used to detect the user's submission status. If the "Submit" button is clicked, the button is immediately disabled and the user cannot click the button to submit again.

There is another method, which also uses the function of JavaScript, but uses the OnSubmit() method. If the form has been submitted once, a dialog box will pop up immediately. The code is as follows:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> </span><span class="tag-name">input</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"hidden"</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"originator"</span><span> </span><span class="attribute">value</span><span>=</span><span class="attribute-value">"=$code?>"</span><span class="tag">></span><span> </span></span></span></li>
<li><span>在接收页面的PHP代码如下：  </span></li>
<li class="alt"><span class="tag"><span> ?phpsession_start();if(isset($_POST['originator'])) {  </span></span></li>
<li><span>if($_POST['originator'] == $_SESSION['code']){// 处理该表单的语句，省略  </span></li>
<li class="alt"><span>}else{  </span></li>
<li><span>echo ‘请不要刷新本页面或重复提交表单！’;  </span></li>
<li class="alt"><span>}  </span></li>
<li>
<span>}</span><span class="tag">?></span><span> </span>
</li>
</ol>

In the above example, if the user has clicked the "Submit" button, the script will automatically record the current status and increment the submitcount variable by
1. When the user tries to submit again, the script will judge the submitcount variable. A non-zero value indicates to the user that the form has already been submitted, thus avoiding repeated submission of the form.

2. Use Cookie Processing
Use Cookie to record the status of form submission. Based on its status, you can check whether the form has been submitted. Please see the following code:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> ?php  </span></span></span></li>
<li><span>if(isset($_POST['go'])){setcookie("tempcookie","",time()+30);  </span></li>
<li class="alt"><span>header("Location:".$_SERVER[PHP_SELF]);exit();  </span></li>
<li><span>} if(isset($_COOKIE["tempcookie"])){  </span></li>
<li class="alt"><span>setcookie("tempcookie","",0);echo "您已经提交过表单";  </span></li>
<li>
<span>}</span><span class="tag">?></span><span> </span>
</li>
</ol>

If the client disables cookies, this method will have no effect. Please note this.

3． Use Session Processing
Using PHP's Session function can also avoid repeated submission of PHP forms. Session is saved on the server side. The Session variable can be changed while PHP is running. The next time you access this variable, you will get the newly assigned value. Therefore, you can use a Session variable to record the value submitted by the form. If it does not match, it is considered The user is submitting repeatedly, please see the following code:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> ?php  </span></span></span></li>
<li><span>session_start();//根据当前SESSION生成随机数  </span></li>
<li class="alt">
<span>$</span><span class="attribute">code</span><span> = </span><span class="attribute-value">mt_rand</span><span>(0,1000000);  </span>
</li>
<li><span>$_SESSION['code'] = $code;  </span></li>
<li class="alt">
<span class="tag">?></span><span> </span>
</li>
</ol>

Pass the random number as a hidden value on the page form, the code is as follows:

<ol class="dp-xml"><li class="alt"><span><span class="tag"><span> </span><span class="tag-name">input</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"hidden"</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"originator"</span><span> </span><span class="attribute">value</span><span>=</span><span class="attribute-value">""</span><span class="tag">></span><span> </span></span></span></li></ol>

While receiving The PHP code of the page is as follows:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> ?php  </span></span></span></li>
<li><span>session_start();  </span></li>
<li class="alt"><span>if(isset($_POST['originator'])) {  </span></li>
<li><span>if($_POST['originator'] == <br>$_SESSION['code']){  </span></li>
<li class="alt"><span>// 处理该表单的语句，省略  </span></li>
<li><span>}else{  </span></li>
<li class="alt"><span>echo ‘请不要刷新本页面或<br>重复提交表单！’;  </span></li>
<li><span>}  </span></li>
<li class="alt">
<span>}</span><span class="tag">?></span><span> </span>
</li>
</ol>

4. Use the header function to redirect to
In addition to the above prevention method of repeated submission of PHP forms, there is a simpler method, that is, when the user submits the form, the server side processes it and immediately redirects to other pages. The code is as follows shown.

<ol class="dp-xml">
<li class="alt"><span><span>if (isset($_POST['action']) <br>&& $_POST['action'] == 'submitted') {  </span></span></li>
<li><span>//处理数据，如插入数据后，立即转向到其他页面  </span></li>
<li class="alt"><span>header('location:submits_success.php');  </span></li>
<li><span>}  </span></li>
</ol>

The above is an introduction to several prevention methods for repeated submission of PHP forms.

http://www.bkjia.com/PHPjc/446204.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446204.htmlTechArticleWhen the user clicks the submit button, the button will become gray and unavailable. In the above example, the OnClick event is used to detect the user's submission status. If the submit button is clicked, the button...