1、提交按钮置disabled
当用户提交后,立即把按钮置为不可用状态。这种用js来实现。
提交前代码如下:
$("#submit").attr('disabled','true');
$("#submit").val("正在提交,请稍等");
执行后,把按钮置为原来状态
代码如下:
$('#submit ').removeAttr('disabled');
$("#submit ").val("确定提交");
这样只是针对一些简单的前台提交了,如果我们自己做个表单站长提交给我们php逻辑层文件就过滤这那个js了。
过期时间法
用户提交按钮后生成一个token(每次业务提交token 为唯一值)存入session,并设置过期时间。当用户再此提交时,检测token是否一致且是否过期,若一致且没有过期,则认为提交了二次
例子
/*
* PHP简单利用token防止表单重复提交
* 此处理方法纯粹是为了给初学者参考
*/
session_start();
function set_token() {
$_SESSION['token'] = md5(microtime(true));
}
function valid_token() {
$return = $_REQUEST['token'] === $_SESSION['token'] ? true : false;
set_token();
return $return;
}
//如果token为空则生成一个token
if(!isset($_SESSION['token']) || $_SESSION['token']=='') {
set_token();
}
if(isset($_POST['test'])){
if(!valid_token()){
echo "token error";
}else{
echo '成功提交,Value:'.$_POST['test'];
}
}
?>
方法二
//开启session
session_start();
//如果有提交标识
if(isset($_GET['action']) && $_GET['action'] === 'save'){
//如果有session且跟传过来的值一样才算提交
if(isset($_SESSION['__open_auth']) && isset($_POST['auth']) && $_SESSION['__open_auth'] == $_POST['auth']){
print_r($_POST);
$_SESSION['__open_auth'] = null;//清空
} else {
//走起
header("location: post.php");
}
exit();
}
//授权
$auth = $_SESSION['__open_auth'] = time();
?>
mysql php数据库重复记录防止
$link=mysql_connect(‘localhost’,’root’,’root’); //得到MySQL数据库连接
$username=$_GET["name"]; //得到从客户端表单传过来的数据
$q="select * from usertable where user_name='$username'";
mysql_query("SET NAMES gb2312"); //避免出现中文乱码
$rs = mysql_query($q, $link); //查询数据库
$num_rows = mysql_num_rows($rs); //得到查询结果的总行数
if($num_rows==0)
{
$exec="insert into student (user_name) values ($username)";
mysql_query("SET NAMES gb2312");
mysql_query($exec, $link); //若没有此用户则将数据插入到数据库(注册用户)
echo "用户注册成功!";
}
else
{
echo "该用户名已存在,请重新选择用户名!";
}
?>
session过期法有非常重要的一点是一个session设置与提交成功与不成功时的一个session验证了,这个有点像登录一样的如果登录成功了我们要清除session这个原理也差不多。
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