php验证码
PHP写的验证码
Demo.php
1 function _code($_width = 75,$_height = 25,$_rnd_code = 4,$_flag = false) {
2
3 //创建随机码
4 for ($i=0;$i<$_rnd_code;$i++) {
5 $_nmsg .= dechex(mt_rand(0,15));
6 }
7
8 //保存在session
9 $_SESSION['code'] = $_nmsg;
10
11 //创建一张图像
12 $_img = imagecreatetruecolor($_width,$_height);
13
14 //白色
15 $_white = imagecolorallocate($_img,255,255,255);
16
17 //填充
18 imagefill($_img,0,0,$_white);
19
20 if ($_flag) {
21 //黑色,边框
22 $_black = imagecolorallocate($_img,0,0,0);
23 imagerectangle($_img,0,0,$_width-1,$_height-1,$_black);
24 }
25
26 //随即画出6个线条
27 for ($i=0;$i<6;$i++) {
28 $_rnd_color = imagecolorallocate($_img,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
29 imageline($_img,mt_rand(0,$_width),mt_rand(0,$_height),mt_rand(0,$_width),mt_rand(0,$_height),$_rnd_color);
30 }
31
32 //随即雪花
33 for ($i=0;$i<100;$i++) {
34 $_rnd_color = imagecolorallocate($_img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255));
35 imagestring($_img,1,mt_rand(1,$_width),mt_rand(1,$_height),'*',$_rnd_color);
36 }
37
38 //输出验证码
39 for ($i=0;$i<strlen($_SESSION['code']);$i++) {
40 $_rnd_color = imagecolorallocate($_img,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200));
41 imagestring($_img,5,$i*$_width/$_rnd_code+mt_rand(1,10),mt_rand(1,$_height/2),$_SESSION['code'][$i],$_rnd_color);
42 }
43
44 //输出图像
45 header('Content-Type: image/png');
46 imagepng($_img);
47
48 //销毁
49 imagedestroy($_img);
50 }
上面的代码写在Demo.php
这是Demo.php将是一个图片，此时想调用验证码
只需在Demo1.php中使用:<img id="code" src="Demo.php" />
如果想点击图片使验证码发生改变:
<script type="text/javascript">
var code = document.getElementById('code');
code.onclick = function(){
this.src='code.php?tm='+Math.random();
}
</script>
