PHP Digital Operation Verification Code implementation Code _php instance

This article describes the PHP implementation of digital verification code method, the implementation of the following methods:

<?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, $black);
 for ($i = 0; $i < $i + +) {Imagesetpixel ($img, rand (0, $w), rand (0, $h), $gray);
 $num 1 = rand (1,99);
 
 $num 2 = rand (1,99);
 Imagestring ($img, 5, 5, rand (1,10), $num 1, $red);
 Imagestring ($img, 5,30,rand (1,10), Getrand (), $white);
 Imagestring ($img, 5,45,rand (1,10), $num 2, $green);
 Imagestring ($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;
 }}?>

Implementation effect:

The above is the use of PHP implementation of digital Verification code method, I hope that the learning of everyone help.