本文分享了php实现可运算的验证码的代码实例，希望对大家的学习有所帮助。
demo.php代码
<?php session_start(); if(!emptyempty($_POST["Login"])){ if(md5(strtoupper($_POST["Login"])) == $_SESSION["Login"]){ echo "Correct"; }else{ echo "Error"; } } ?> <form method="post"> <input type="text" name="Login" value="" /><img src="img.php?Action=Login&imgW=80&imgH=30" align="absmiddle"> <input type="submit" value="Login" /> </form> img.php代码
<?php session_start(); /** * 随机的数字,之和验证码 * 修改日期 2006-12-20 */ function getCode ($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 $result; } //建立验证图片 function createAuthNumImg($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"); ?> 以上就是为大家介绍的php可运算的验证码全部代码，希望对大家的学习有所帮助。
