Perfect PHP generation verification code program code_PHP tutorial

This article introduces you to a very good php program for generating verification codes. First, when the user requests HTTP, the server creates a unique sessionid. This is the session ID, and then starts the GD library or imagemagick. These drawing tools write random characters generated by the program into a picture, then display it to the client, and then the user inputs and submits the data. Then our program saves the generated verification in the session for comparison, thus completing the verification code. generated and verified.

•Create a new PHP file captcha_code_file.php

The code is as follows

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代码如下

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//首先开启session session_start(); //定义前台显示验证码长&宽 $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"; //定义要生成验证码的字符串 $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 //设置session，做验证 $_SESSION['6_letters_code'] = $code; function hexrgb ($hexstr) { $int = hexdec($hexstr); return array("red" => 0xFF & ($int >> 0x10),                "green" => 0xFF & ($int >> 0x8),                "blue" => 0xFF & $int); }

//Open session first
session_start();
//Define the length & width of the verification code displayed in the front desk
$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";
//Define the string to generate the verification code
$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 colors 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
//Set up session and do verification
$_SESSION['6_letters_code'] = $code;<🎜> <🎜>function hexrgb ($hexstr)
{
$int = hexdec($hexstr);<🎜> <🎜> return array("red" => 0xFF & ($int >> 0x10),
"green" => 0xFF & ($int >> 0x8),
"blue" => 0xFF & $int);
}

Calling the page to display the verification code page index.php

The code is as follows

 代码如下

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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="您输入的验证码有误，请重新输入!";
}else{
echo "您输入的是正确的!";
// Captcha verification is Correct. Final Code Execute here!
}
}
?>

 

   
     
   

   
     
     
   
   
     
     
   
 

验证码Demo:	请输入验证码:                                 如果看不到，请 点我 刷新一下!

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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="The verification code you entered is incorrect, please re-enter it!";
}else{
echo "What you entered is correct!";
// Captcha verification is Correct. Final Code Execute here!
}
} 
?>

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Verification code Demo:	Please enter the verification code:                                                                                                                                                                               If you can’t see it, please Click me to refresh it!

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http: //www.bkjia.com/PHPjc/632957.htmlTechArticleThis article introduces you to a very good php program that generates verification codes. First, when the user requests HTTP, The server creates a unique sessionid, which is the session...