Php code for implementing the verification code for digital operation

This article mainly introduces the php method for implementing the digital operation verification code, which has some reference value. if you need it, you can refer to the example below to describe how php implements the digital operation verification code, the specific implementation method is as follows:

<?phpgetValidate(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;  }} ?>

Effect:

The above describes how to use php to implement the verification code for digital computation. I hope it will be helpful for your learning.