<?php        getValidate(100,30);                function getValidate($w,$h){            $img = imagecreate($w,$h);                    $gray = imagecolorallocate($img,255,255,255);            $black = imagecolorallocate($img,rand(0,200),rand(0,200),rand(0,200));            $red = imagecolorallocate($img, 255, 0, 0);            $white = imagecolorallocate($img, 255, 255, 255);            $green = imagecolorallocate($img, 0, 255, 0);            $blue = imagecolorallocate($img, 0, 0, 255);            imagefilledrectangle($img, 0, 0, 100, 30, $black);                            for($i = 0;$i < 80;$i++){                imagesetpixel($img, rand(0,$w), rand(0,$h), $gray);            }                            $num1 = rand(1,99);            $num2 = rand(1,99);                    imagestring($img, 5, 5, rand(1,10), $num1, $red);            imagestring($img,5,30,rand(1,10),getRand(), $white);            imagestring($img,5,45,rand(1,10),$num2, $green);            imagestring($img,5,65,rand(1,10),"=", $blue);            imagestring($img,5,80,rand(1,10),"?", $red);                                header("content-type:image/png");            imagepng($img);            imagedestroy($img);        }        function getRand(){            $code = rand(0,1);            switch ($code) {                case 0:                    return "+";                    break;                case 1:                    return "-";                    break;                default:                    # code...                    break;            }        }                ?>