Several methods of PHP verification code generation program

The function of PHP verification code generation is often used as a basic security verification function when users register, log in or publish information. The following editor will introduce to you some commonly used PHP verification code generation codes and application examples.

Example 1, use array directly, this method is relatively simple

The code is as follows

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$arr=array(2,3,4,5,8,1,9,7,"a","b","c","d","e","f","中","国","南","北","大","小","多","少");
$b=array_rand($arr,3);

echo “code:";
foreach($b as $key)
{
echo $arr[$key];
}
?>

（以上语句另存为一个php文件）

header(“Content-Type:text/html;charset=utf-8");
echo $_POST["yanzhengma"];
echo $_POST["code"];
if($_POST["yanzhengma"]==$_POST["code"])
{
echo “验证码正确";
}
else
{
die(“<script>alert(‘验证码不正确");location="array_rand.php";</script>");
}
?>

<🎜>$arr=array(2,3,4,5,8,1,9,7,"a","b","c","d","e","f","中","国","南","北","大","小","多","小");
$b=array_rand($arr,3);<🎜> <🎜>?>

<🎜>echo “code:”;
foreach($b as $key)
{
echo $arr[$key];
}
?>
(Save the above statement as a php file) header("Content-Type:text/html;charset=utf-8");
echo $_POST["yanzhengma"];
echo $_POST["code"];
if($_POST["yanzhengma"]==$_POST["code"])
{
echo "Verification code is correct";
}
else
{
die("<script>alert('Verification code is incorrect");location="array_rand.php";</script>");
}
?>

(Save the above statement as yz.php)

Example 2 also uses an array, but there is a little more data

The code is as follows

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代码如下

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UPCAbarcode('12345678901');

Example 3, this is a relatively complete example of ajax refresh verification code

vcode.php

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session_start();//开启session功能
header("Cache-Control: no-cache, must-revalidate");

$im = imagecreate(60,30);//定义图片宽度和高度
$vcode=getVCode();//获取要显示的字符
$bg = imagecolorallocate($im, 255, 255, 255);//定义图片背景
$txt = imagecolorallocate($im, rand(0,255), rand(0,255), rand(0,255));//定义要显示字符的颜色
imagestring($im, 8, 0, 0, $vcode, $txt);//写入字符串到图片
header(Content-type: image/jpeg);//定义Content-type
imagejpeg($im);//以JPEG格式显示图片
$_SESSION[vcode]=$vcode;//写入SESSION

function getVCode(){ //随机生成用户指定个数的字符串
$codenum=4;
$checkcode="";
$string="";//要显示的可选字符串，请自行定义；
for($i=0;$i<$codenum;$i ) {
$number=rand(0,2);
switch($number){ //根据可选字符串可灵活定义；
case 0 : $rand_number=rand(0,10);break;
case 1 : $rand_number=rand(11,36);break;
case 2 : $rand_number=rand(37,62);break;
}
$code=substr($string,$rand_number,1);
$checkcode=$checkcode.$code;
}
return $checkcode;
}
?>

session_start();//Enable session function <🎜> header("Cache-Control: no-cache, must-revalidate");<🎜> <🎜>$im = imagecreate(60,30);//Define image width and height <🎜> $vcode=getVCode();//Get the characters to be displayed <🎜> $bg = imagecolorallocate($im, 255, 255, 255);//Define image background <🎜> $txt = imagecolorallocate($im, rand(0,255), rand(0,255), rand(0,255)); //Define the color of the characters to be displayed <🎜> imagestring($im, 8, 0, 0, $vcode, $txt);//Write string to image <🎜> header(Content-type: image/jpeg);//Define Content-type <🎜> imagejpeg($im);//Display images in JPEG format <🎜> $_SESSION[vcode]=$vcode;//Write SESSION <🎜> <🎜> function getVCode(){ //Randomly generate a user-specified number of strings <🎜> $codenum=4; <🎜> $checkcode=""; <🎜> $string="";//Optional string to be displayed, please define it yourself; <🎜> for($i=0;$i<$codenum;$i ) { <🎜> $number=rand(0,2); <🎜> switch($number){ //can be flexibly defined according to the optional string; <🎜> case 0: $rand_number=rand(0,10);break; case 1: $rand_number=rand(11,36);break; case 2: $rand_number=rand(37,62);break; } <🎜> $code=substr($string,$rand_number,1); <🎜> $checkcode=$checkcode.$code; <🎜> } <🎜> Return $checkcode; <🎜> } <🎜> ?>

loginform.html

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vcode.js

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//该函数用来获取验证码

function getVCode() {
var vcode=document.getElementById('vcode');
vcode.src = 'vcode.php?nocache='+new Date().getTime();
}

//该函数用来验证验证码
function usrVCode() {
        if(!checkLogin())return false;
        var loginvcode=document.loginform.loginvcode.value;
        var xmlhttp1=createAjax();
        var data='&loginvcode='+loginvcode;
if (xmlhttp1) {
var state=document.getElementById('state');
          xmlhttp1.open('get',?do=vcodedo'+data,true);
xmlhttp1.send(null);
xmlhttp1.onreadystatechange=function() {
    if (xmlhttp1.readyState==4 && xmlhttp1.status==200) {
             setTimeout("state.style.display = 'none';",1000);
     var myres=xmlhttp1.responseText;
             var result=(myres==1)?"恭喜您,验证码输入正确!":"很抱歉,验证码输入错误!";
             if(myres==0)alert(result);
             if(myres==1)usrLogin();
            }
    else {
             state.style.display = "";
     state.style.left=(document.body.offsetWidth-350)/2;
             state.style.top=(document.body.offsetHeight-235)/2+document.body.scrollTop;
    }
          }
}
}

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//This function is used to obtain the verification code

function getVCode() {
var vcode=document.getElementById('vcode');
vcode.src = 'vcode.php?nocache='+new Date().getTime();
}

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Several methods of PHP verification code generation program_PHP tutorial