Generate verification code in php_PHP tutorial-PHP Tutorial-php.cn

Generate verification code in php_PHP tutorial

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Release： 2016-07-13 17:07:08

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PHP generating verification code files is a technology that friends who learn PHP should know. This can not only improve the security of your website, but also prevent some problems such as machine registration. Below we will Let’s take a look at a simple program to generate verification codes

php verification code generation file is a technology that friends who learn PHP should know. This can not only improve the security of your website, but also You can avoid some problems such as machine registration. Let’s take a look at a simple generating verification code program

/eckNum.php
session_start();
function random(){
$srcstr="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
mt_srand();
$strs="";
for($i=0;$i<6;$i++){
$strs.=$srcstr[mt_rand(0,35)];
}
return strtoupper($strs);
}
$str=random(4); //Just use the string generated by the machine
$width = 50; //Width of verification code image
$height = 25; //Height of verification code image
@header("Content-Type:image/png");
$_SESSION["code"] = $str;
//echo $str;
$im=imagecreate($width,$height);
//Background color
$back=imagecolorallocate($im,0xFF,0xFF,0xFF);
//Blur 97xxoo point color
$pix=imagecolorallocate($im,187,230,247);
//Font color
$font=imagecolorallocate($im,41,163,238);
//Draw the blur effect point
mt_srand();
for($i=0;$i<1000;$i++)
{
imagesetpixel($im,mt_rand(0,$width),mt_rand(0,$height),$pix);
}
imagestring($im, 5, 7, 5,$str, $font);
imagerectangle($im,0,0,$width-1,$height-1,$font);
imagepng($im);
imagedestroy($im);
$_SESSION["code"] = $str;
?>