PHP verification code implementation code simple example _ PHP Tutorial

Simple example of PHP verification code implementation code. I have talked about a lot of PHP verification code examples. next I will turn to a friend's good PHP verification code program, which is quite simple for your reference. I have talked a lot about the php verification code for some PHP examples. next I will turn to a friend's PHP verification code program, which is quite simple for your reference.

Recently I am bored and have nothing to do. I started to share some php code, which is simple but practical.

This was written four years ago. several lines of code implement the php verification code function with four random numbers.

The code is as follows:

Session_start (); Header ("Content-type: image/jpeg "); $ Img = imagecreate (50, 20 ); $ White = imagecolorallocate ($ img, 211,213,193 ); Imagefill ($ img, 0, 0, $ white ); For ($ I = 0; $ I <4; $ I ++ ){ $ R [$ I] = rand (0, 9 ); } $ _ SESSION ['valid'] = implode ("", $ r); // write it here for post-verification. For ($ I = 0; $ I <4; $ I ++ ){ If (rand (0, 9) % 2 = 0 ){ Imagechar ($ img, 5, ($ I + 1) * 8, 4, $ r [$ I], imagecolorallocate ($ img, rand (0,150), rand (0,150 ), rand (0,150 ))); } Else { Imagechar ($ img, 5, ($ I + 1) * 8, 2, $ r [$ I], imagecolorallocate ($ img, rand (0,150), rand (0,150 ), rand (0,150 ))); } } Imagejpeg ($ img );

Bytes. I 've been bored recently, so I started to do some php...