How to create php verification code?

php verification code production is an assessment of basic PHP skills. PHP verification code production must open the gd library because it uses many functions in the gd library

Recommended LearnPHP development verification codeTutorial

1. Create a verification code base map

<?php
$image = imagecreatetruecolor(100,30);
$bgcolor = imagecolorallocate($image,000,255,255);//#FFFFFFFFFFFF
imagefill($image,0,0,$bgcolor);

header(&#39;content-type: image/png&#39;);
imagepng($image);
//销毁
imagedestroy($image);
?>

Course link: http://www.php.cn/code/3872.html

2.Implementing digital verification code

<?php
$image = imagecreatetruecolor(100,30);
$bgcolor = imagecolorallocate($image,255,255,255);//#FFFFFFFFFFFF
imagefill($image,0,0,$bgcolor);
for ($i=0;$i<4;$i++){
 $fontsize = 6;
 $fontcolor = imagecolorallocate($image,rand(0,120),rand(0,120),rand(0,120));
 $fontcontent = rand(0,9);
 $x = ($i * 100/4)+rand(5,10);
 $y = rand(5,10);
 imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);
}
header(&#39;content-type: image/png&#39;);
imagepng($image);
//销毁
imagedestroy($image);

?>

Course Link: http://www.php.cn/code/3874.html

3.Add disturbing elements

<?php
$image = imagecreatetruecolor(100,30);
$bgcolor = imagecolorallocate($image,255,255,255);//#FFFFFFFFFFFF
imagefill($image,0,0,$bgcolor);
for ($i=0;$i<4;$i++){
 $fontsize = 6;
 $fontcolor = imagecolorallocate($image,rand(0,120),rand(0,120),rand(0,120));
 $fontcontent = rand(0,9);
 $x = ($i * 100/4)+rand(5,10);
 $y = rand(5,10);
 imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);
}
for($i=0;$i<200;$i++){
 $pointcolor = imagecolorallocate($image,rand(50,200),rand(50,200),rand(50,200));
 imagesetpixel($image,rand(1,99),rand(1,29),$pointcolor);
}
header(&#39;content-type: image/png&#39;);
imagepng($image);
//销毁
imagedestroy($image);
?>

Course link: http://www.php.cn/code/3875.html

4.Mixed letters and numbers verification code

<?php
$image = imagecreatetruecolor(100,30);
$bgcolor = imagecolorallocate($image,255,255,255);//#FFFFFFFFFFFF
imagefill($image,0,0,$bgcolor);
for ($i=0;$i<4;$i++){
 $fontsize = 6;
 $fontcolor = imagecolorallocate($image,rand(0,120),rand(0,120),rand(0,120));
 $data=&#39;abcdefghijklmnopqrstuvwxyz1234567890&#39;;
 $fontcontent=substr($data,rand(0,strlen($data)),1);
 $x = ($i * 100/4)+rand(5,10);
 $y = rand(5,10);
 imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);
}
for($i=0;$i<200;$i++){
 $pointcolor = imagecolorallocate($image,rand(50,200),rand(50,200),rand(50,200));
 imagesetpixel($image,rand(1,99),rand(1,29),$pointcolor);
}
for($i=0;$i<8;$i++){
 $linecolor = imagecolorallocate($image,rand(60,220),rand(60,220),rand(60,220));
 imageline($image,rand(1,99),rand(1,29),rand(1,99),rand(1,29),$linecolor);
}
header(&#39;content-type: image/png&#39;);
imagepng($image);
//销毁
imagedestroy($image);

?>

Course link: http://www.php.cn/code/3878.html

##5.

Use session to store verification information

<?php
session_start();
$image = imagecreatetruecolor(100,30);
$bgcolor = imagecolorallocate($image,255,255,255);//#FFFFFFFFFFFF
imagefill($image,0,0,$bgcolor);
$captch_code="";
for ($i=0;$i<4;$i++){
 $fontsize = 6;
 $fontcolor = imagecolorallocate($image,rand(0,120),rand(0,120),rand(0,120));
 $data=&#39;abcdefghijklmnopqrstuvwxyz1234567890&#39;;
 $fontcontent=substr($data,rand(0,strlen($data)),1);
 $captch_code.="$fontcontent";
 $x = ($i * 100/4)+rand(5,10);
 $y = rand(5,10);
 imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);
}
$_SESSION[&#39;code&#39;]=$captch_code;
for($i=0;$i<200;$i++){
 $pointcolor = imagecolorallocate($image,rand(50,200),rand(50,200),rand(50,200));
 imagesetpixel($image,rand(1,99),rand(1,29),$pointcolor);
}
for($i=0;$i<8;$i++){
 $linecolor = imagecolorallocate($image,rand(60,220),rand(60,220),rand(60,220));
 imageline($image,rand(1,99),rand(1,29),rand(1,99),rand(1,29),$linecolor);
}
header(&#39;content-type: image/png&#39;);
imagepng($image);
//销毁
imagedestroy($image);
?>

Course link: http://www.php.cn/code/3879.html

6.

Use of verification code

<?php
session_start();
$image = imagecreatetruecolor(100,30);
$bgcolor = imagecolorallocate($image,255,255,255);//#FFFFFFFFFFFF
imagefill($image,0,0,$bgcolor);
$captch_code="";
for ($i=0;$i<4;$i++){
 $fontsize = 6;
 $fontcolor = imagecolorallocate($image,rand(0,120),rand(0,120),rand(0,120));
 $data=&#39;abcdefghijklmnopqrstuvwxyz1234567890&#39;;
 $fontcontent=substr($data,rand(0,strlen($data)),1);
 $captch_code.="$fontcontent";
 $x = ($i * 100/4)+rand(5,10);
 $y = rand(5,10);
 imagestring($image,$fontsize,$x,$y,$fontcontent,$fontcolor);
}
$_SESSION[&#39;code&#39;]=$captch_code;
for($i=0;$i<200;$i++){
 $pointcolor = imagecolorallocate($image,rand(50,200),rand(50,200),rand(50,200));
 imagesetpixel($image,rand(1,99),rand(1,29),$pointcolor);
}
for($i=0;$i<5;$i++){
 $linecolor = imagecolorallocate($image,rand(60,220),rand(60,220),rand(60,220));
 imageline($image,rand(1,99),rand(1,29),rand(1,99),rand(1,29),$linecolor);
}
header(&#39;content-type: image/png&#39;);
imagepng($image);
//销毁
imagedestroy($image);
?>

## Course link: http://www.php.cn/code/4832. html

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