本文分享了php實現(xiàn)可運算的驗證碼的代碼實例，希望對大家的學習有所幫助。

demo.php代碼

<?php

session_start();

if(!emptyempty($_POST['Login'])){

if(md5(strtoupper($_POST['Login'])) == $_SESSION['Login']){

echo 'Correct';

}else{

echo 'Error';

}

}

?>

<form method="post">

<input type="text" name="Login" value="" /><img src="img.php?Action=Login&imgW=80&imgH=30" align="absmiddle">

<input type="submit" value="Login" />

</form>

img.php代碼

<?php

session_start();

/**

* 隨機的數(shù)字,之和驗證碼

* 修改日期 2006-12-20

*/

function getCode ($length = 32, $mode = 0)

{

switch ($mode)

{

case '1':

$str = '123456789';

break;

case '2':

$str = 'abcdefghijklmnopqrstuvwxyz';

break;

case '3':

$str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';

break;

case '4':

$str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

break;

case '5':

$str = 'ABCDEFGHIJKLMNPQRSTUVWXYZ123456789';

break;

case '6':

$str = 'abcdefghijklmnopqrstuvwxyz1234567890';

break;

default:

$str = 'ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz23456789';

break;

}

$result = '';

$l = strlen($str)-1;

for($i = 0;$i < $length;$i ++)

{

$num = rand(0, $l);

$result .= $str[$num];

}

return $result;

}

//建立驗證圖片

function createAuthNumImg($randStr,$imgW=100,$imgH=40,$fontName)

{

header ("content-type: image/png");

$image = imagecreate($imgW , $imgH);

$color_white = imagecolorallocate($image , 255 , 255 , 255);

$color_gray = imagecolorallocate($image , 228 , 228 , 228);

$color_black = imagecolorallocate($image , 255 , 102 , 204);

for ($i = 0 ; $i < 1000 ; $i++)

{

imagesetpixel($image , mt_rand(0 , $imgW) , mt_rand(0 , $imgH) , $color_gray);

}

imagerectangle($image , 0 , 0 , $imgW - 1 , $imgH - 1 , $color_gray);

for ($i=10;$i<$imgH;$i+=10)

imageline($image, 0, $i, $imgW, $i, $color_gray);

imagettftext($image,16,5,3,25,$color_black,$fontName,$randStr);

for ($i=10;$i<$imgW;$i+=10)

imageline($image, $i, 0, $i, $imgH, $color_gray);

imagepng($image);

imagedestroy($image);

}

$a=GetCode(1,1);

$b=GetCode(1,1);

$c=GetCode(1,1);

$Passport=$a."+".$b."+".$c;

$Total=$a+$b+$c;

$Total;

$_SESSION[$_GET['Action']]=md5(strtoupper($Total));

createAuthNumImg($Passport,$_GET['imgW'],$_GET['imgH'],"verdana.ttf");

?>

以上就是為大家介紹的php可運算的驗證碼全部代碼，希望對大家的學習有所幫助。