完美的php產生驗證碼程式碼_PHP教程

本文章給大家介紹一個非常不錯的產生驗證碼的php程式，首先當使用者請求HTTP的時候，伺服器端就建立一個唯一的sessionid，這個是session會話ID，然後就去啟動GD庫或者imagemagick這些畫圖工具，把程式產生的隨機的字元寫到一張圖片裡面，然後顯示到用戶端,再由使用者輸入提交資料，然後我們程式把產生驗證儲存在session中進行比較，這樣就完成了驗證碼的產生與驗證了。

•建立一個PHP檔案captcha_code_file.php

代碼如下

複製代碼

//首先開啟session session_start(); //定義前台顯示驗證碼長&寬 $image_width = 120; $image_height = 40; $characters_on_image = 6; $font = './monofont.ttf'; //The characters that can be used in the CAPTCHA code. //avoid confusing characters (l 1 and i for example) $possible_letters = '23456789bcdfghjkmnpqrstvwxyz'; $random_dots = 10; $random_lines = 30; $captcha_text_color="0x142864"; $captcha_noice_color = "0x142864"; //定義要產生驗證碼的字串 $code = ''; $i = 0; while ($i < $characters_on_image) { $code .= substr($possible_letters, mt_rand(0, strlen($possible_letters)-1), 1); $i++; } $font_size = $image_height * 0.75; $image = @imagecreate($image_width, $image_height); /* setting the background, text and noise colours here */ $background_color = imagecolorallocate($image, 255, 255, 255); $arr_text_color = hexrgb($captcha_text_color); $text_color = imagecolorallocate($image, $arr_text_color['red'], $arr_text_color['green'], $arr_text_color['blue']); $arr_noice_color = hexrgb($captcha_noice_color); $image_noise_color = imagecolorallocate($image, $arr_noice_color['red'], $arr_noice_color['green'], $arr_noice_color['blue']); /* generating the dots randomly in background */ for( $i=0; $i<$random_dots; $i++ ) { imagefilledellipse($image, mt_rand(0,$image_width), mt_rand(0,$image_height), 2, 3, $image_noise_color); } /* generating lines randomly in background of image */ for( $i=0; $i<$random_lines; $i++ ) { imageline($image, mt_rand(0,$image_width), mt_rand(0,$image_height), mt_rand(0,$image_width), mt_rand(0,$image_height), $image_noise_color); } /* create a text box and add 6 letters code in it */ $textbox = imagettfbbox($font_size, 0, $font, $code); $x = ($image_width - $textbox[4])/2; $y = ($image_height - $textbox[5])/2; imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code); /* Show captcha image in the page html page */ header('Content-Type: image/jpeg');// defining the image type to be shown in browser widow imagejpeg($image);//showing the image imagedestroy($image);//destroying the image instance //設定session，做驗證 $_SESSION['6_letters_code'] = $code; function hexrgb ($hexstr) { $int = hexdec($hexstr); return array("red" => 0xFF & ($int >> 0x10), "green" => 0xFF & ($int >> 0x8), "blue" => 0xFF & $int); }

調用頁面顯示驗證碼頁面index.php

代碼如下	複製代碼
session_start(); if(isset($_REQUEST['Submit'])){ // code for check server side validation if(empty($_SESSION['6_letters_code'] ) || strcasecmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0) { $msg="您輸入的驗證碼有誤，請重新輸入!"; }else{ echo "您輸入的是正確的!"; // Captcha verification is Correct. Final Code Execute here! } } ?>

http://www.bkjia.com/PHPjc/632957.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/632957.htmlTechArticle本文章給大家介紹一個非常不錯的產生驗證碼的php程式，首先當使用者請求HTTP的時候，伺服器端就建立一個唯一的sessionid，這個是session會話...

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