解决表单重复提交问题的PHP代码

<script type="text/javascript">
var checkSubmitFlg = false;
function checkSubmit() {
if (!checkSubmitFlg) {

// 第一次提交
checkSubmitFlg = true;
return true;
} else {

//重复提交
alert("Submit again!");
return false;
}
}
</script>

//以下三种方式分别调用

<form onsubmit="return checkSubmit();">

<input type="submit" onclick="return checkSubmit();" />

<input type="button" onclick="s[0]on='./test';s[0]it();return checkSubmit();" />

<form

method="post">
<p>
<label for="test">随便输入点什么</label>
<input type="text" name="data" id="test" />
</p>
<p>
<input type="submit" value="提交" name="submit" />
</p>
</ul>
</form>

http://localhost/mytest/token/

<?php
if ( isset( $_POST['submit'] ) ) {
//表单提交处理
$data = isset(

$_POST['data'] ) ? htmlspecialchars( $_POST['data'] ) : '';
//connect
mysql_connect( 'localhost', 'root', 'root' );

//select db
mysql_select_db( 'test' );
//设置字符集防止乱码
mysql_query( 'set names "utf8"' );
//SQL
$sql = "insert

into `token` (string) values ('$data')";
//query
mysql_query( $sql );
$insert_id = mysql_insert_id();
if (

$insert_id ) {
$state = 1;
} else {
$state = 0;
}
}
?>

<?php if ( isset( $state )

&& $state ) { //数据插入成功 ?>

<p>插入成功 <a href="">返回</a></p>

<?php } else { //失败或者没有插入动

作 ?>

<form method="post">

<p>

<label for="test">随便输入点什么</label>

<input type="text"

name="data" id="test" />

</p>

<p>

<input type="submit" value="提交" name="submit" />

</p>

</ul>

</form>

<?php } ?>

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Welcome extends CI_Controller {

public function index()
{
$this->load->view('welcome_message');
}

public function token()
{
$this->load->helper( array('form') );
$this->load->library('form_validation');
if ( $this->input->post( 'submit' ) && $this->form_validation->valid_token() )
{
//nothing
//valid_token已经包含令牌超时与令牌正确的判断，若要启用令牌超时，请将token_validtime设置为非0
echo 'ok';
}

//生成表单令牌
$token = $this->form_validation->create_token();

//form example
echo form_open();
echo form_input('token', '');
echo $token;
echo form_submit('submit', 'submit');
echo form_close();
}
}

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* @abstract 继承CI的Form_validation类在其基础上增加令牌
*/
class MY_Form_validation extends CI_Form_validation {

/**
* 令牌键值
* @var string
*/
var $key = 'token';

/**
* 表单令牌有效时间(秒)
* @abstract 如果某些表单需要限制输入时间，则设置该值，为0则不限制
* @var int 秒
*/
var $token_validtime = 5;

/**
* 调试模式
* @var bool
*/
var $debug = false;

/**
* CI对象
* @var <type>
*/
private $_CI;

public function __construct()
{
parent::__construct();
$this->_CI =& get_instance();
//如果配置没有填写encryption_key
$encryption_key = config_item('encryption_key');
if ( empty( $encryption_key ) ) $this->_CI->config->set_item( 'encryption_key', $this->key );
//如果没有装载session
if ( !isset( $this->_CI->session ) ) $this->_CI->load->library('session');
}

/**
* 设置令牌有效时间
* @param int $second 秒数
*/
public function set_token_validtime( $second )
{
$this->token_validtime = intval( $second );
}

/**
* 获取表单令牌有效时间
* @return int 秒数
*/
public function get_token_validtime()
{
return $this->token_validtime;
}

/**
* 验证表单令牌是否合法
* @return bool
*/
public function valid_token()
{
if ( $this->debug ) return true;
//获取session中的hash
$source_hash = $this->_CI->session->userdata( $this->key );
if ( empty( $source_hash ) ) return false;

//判断是否超时
if ( $this->is_token_exprie() ) return false;

//提交的hash
$post_formhash = $this->_CI->input->post( $this->key );
if ( empty( $post_formhash ) ) return false;

if ( md5( $source_hash ) == $post_formhash )
{
$this->_CI->session->unset_userdata( $this->key );
return true;
}
return false;
}

/**
* 生成表单令牌（连同input元素）
* @return string
*/
public function create_token( $output = false )
{
$code = time() . '|' . $this->get_random( 5 );
$this->_CI->session->set_userdata( $this->key , $code);
$result = function_exists('form_hidden') ? form_hidden( $this->key, md5( $code ) ) : '<input type="hidden" name="token" value="'. md5( $code ) .'" />';
if ( $output )
{
echo $result;
}
else
{
return $result;
}
}

/**
* 获取随机数（自己可以扩展）
* @param int $number 上限
* @return string
*/
public function get_random( $number )
{
return rand( 0, $number );
}

/**
* 判断表单令牌是否过期
* @return bool
*/
public function is_token_exprie()
{
if ( empty( $this->token_validtime ) ) return false;
$token = $this->_CI->session->userdata( $this->key );
if ( empty( $token ) ) return false;
$create_time = array_shift( explode('|', $token) );
return ( time() - $create_time > $this->token_validtime );
}
}