Recommend a PHP Verification code program _php Tutorial

Share a better PHP verification code program, a friend of the need to reference.

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The code is as follows: /* Website Verification Code Program * Operating Environment: PHP5.0.18 under Commissioning * Requires GD2 graphics library support (php.ini in Php_gd2.dll) * File name: showimg.php * Author: 17php.com * date:2007.03 */ Randomly generate a 4-digit number verification code $num = ""; for ($i =0; $i <4; $i + +) { $num. = rand (0,9); } 4-bit verification code can also be generated directly with Rand (1000,9999) Writes the generated verification code to the session and verifies that the page uses Session_Start (); $_session["Checknum"] = $num; Create a picture, define a color value Header ("Content-type:image/png"); Srand (Double) microtime () *1000000); $im = Imagecreate (60,20); $black = Imagecolorallocate ($im, 0,0,0); $gray = Imagecolorallocate ($im, 200,200,200); Imagefill ($im, 0,0, $gray); Randomly draw two dashed lines, play a role in jamming $style = Array ($black, $black, $black, $black, $black, $gray, $gray, $gray, $gray, $gray); Imagesetstyle ($im, $style); $y 1=rand (0,20); $y 2=rand (0,20); $y 3=rand (0,20); $y 4=rand (0,20); Imageline ($im, 0, $y 1, $y 3, img_color_styled); Imageline ($im, 0, $y 2, $y 4, img_color_styled); A large number of black dots are randomly generated on the canvas, which acts as interference; for ($i =0; $i <80; $i + +) { Imagesetpixel ($im, Rand (0,60), Rand (0,20), $black); } Randomly displays four numbers on the canvas, and the horizontal spacing and position of the characters are randomly generated at a certain range of fluctuations $strx =rand (3,8); for ($i =0; $i <4; $i + +) { $strpos =rand (1,6); Imagestring ($im, 5, $strx, $strpos, substr ($num, $i, 1), $black); $strx +=rand (8,12); } Imagepng ($im); Imagedestroy ($im); ?>

How to use:
This program can be run directly, after running can see a graphics verification code, each refresh is randomly generated new code.
When using this program on a page, you can use the following code:
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Please enter the verification code:

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This displays the Captcha picture. To the verification page, use the following code:
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$code =$_post["passcode"]; if ($code = = $_session["Checknum"]) { Validation by }else{ Verification Code Error } ...

http://www.bkjia.com/PHPjc/629690.html www.bkjia.com true http://www.bkjia.com/PHPjc/629690.html techarticle share a better PHP verification code program, a friend of the need to reference. The code below copies the code as follows:? PHP/* Website CAPTCHA Program * Operating environment: PHP5.0.18 down ...

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