Use session in php to avoid repeated submission of forms when refreshing the page

(1) PHP part

session_start();
$sign=$_SESSION['code'];
$sscode=mt_rand(0,1000000);
$this->assign("sscode",$sscode);//将随机值传入html中
if(isset($_POST['submit'])){
    //isset($_POST['submit'])为判断是否有表单提交
    //$_POST['submit_sign']为表单中隐藏域的一个值
    if($_POST['submit_sign']==$sign){
        //处理表单数据  
    }
else{
    echo "<script>alert('请勿重复提交表单')</script>"
}
}</span>

(2) HTML part

<form action="" name="myform" method="post">
<input type="submit" value="提交" name="submit"/>
<input type="hidden" value="<?php echo $sscode?>" name=submit_sign/><!--隐藏域-->
</form></span>

The above introduces the use of session in PHP to avoid repeated submission of forms when refreshing the page, including the content. I hope it will be helpful to friends who are interested in PHP tutorials.