PHP generates image verification code and clicks to switch examples_PHP tutorial

Here is the effect:

Now let’s look at the PHP code

Copy code The code is as follows:

<?php

session_start();
function random($len) {
$srcstr = "1a2s3d4f5g6hj8k9qwertyupzxcvbnm";
mt_srand();
$strs = "";
for ($i = 0; $i < $len; $i++) {
           $strs .= $srcstr[mt_rand(0, 30)];
}
Return $strs;
}

//Randomly generated string
$str = random(4);

//Width of verification code image
$width = 50;

//The height of the verification code image
$height = 25; 

//Declare the image format of the layer to be created
@ header("Content-Type:image/png");

//Create a layer
$im = imagecreate($width, $height);

//Background color
$back = imagecolorallocate($im, 0xFF, 0xFF, 0xFF);

//Blurred 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);
}

//Output character
imagestring($im, 5, 7, 5, $str, $font);

//Output rectangle
imagerectangle($im, 0, 0, $width -1, $height -1, $font);

//Output picture
imagepng($im);

imagedestroy($im);

$str = md5($str);

//Select cookie
//SetCookie("verification", $str, time() + 7200, "/");

//Select Session
$_SESSION["verification"] = $str;
?>

Then just call it on the page:

Copy code The code is as follows:

<img id="checkpic" onclick="changing();" src='/images/checkcode.php' />

If you want to achieve the "Can't see clearly? Change one" effect, add the following JS to the page

Copy code The code is as follows:

function changing(){
Document.getElementById('checkpic').src="/images/checkcode.php?"+Math.random();
}

http://www.bkjia.com/PHPjc/824817.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/824817.htmlTechArticleLet’s take a look at the effect: Now let’s take a look at the PHP code. Copy the code as follows: php session_start(); function random($len) { $srcstr = "1a2s3d4f5g6hj8k9qwertyupzxcvbnm"; mt_s...