英文同数字

<?php

Header("Content-type:image/png");

//定义header，声明图片文件，最好是png，无版权之扰;

//生成新的四位整数验证码

session_start();//开启session;

$authnum_session='';

$str='abcdefghijkmnpqrstuvwxyz1234567890';

//定义用来显示在图片上的数字和字母;

$l=strlen($str);//得到字串的长度;

//循环随机抽取四位前面定义的字母和数字;

for($i=1;$i<=4;$i++)

{

$num=rand(0,$l-1);

//每次随机抽取一位数字;从第一个字到该字串最大长度,

//减1是因为截取字符是从0开始起算;这样34字符任意都有可能排在其中;

$authnum_session.=$str[$num];

//将通过数字得来的字符连起来一共是四位;

}

session_register("authnum_session");

//用session来做验证也不错;注册session,名称为authnum_session,

//其它页面只要包含了该图片

//即可以通过$_SESSION["authnum_session"]来调用

//生成验证码图片，

srand((double)microtime()*1000000);

$im=imagecreate(50,20);//图片宽与高;

//主要用到黑白灰三种色;

$black=ImageColorAllocate($im,0,0,0);

$white=ImageColorAllocate($im,255,255,255);

$gray=ImageColorAllocate($im,200,200,200);

//将四位整数验证码绘入图片

imagefill($im,68,30,$gray);

//如不用干扰线，注释就行了;

$li=ImageColorAllocate($im,220,220,220);

for($i=0;$i<3;$i++)

{//加入3条干扰线;也可以不要;视情况而定，因为可能影响用户输入;

imageline($im,rand(0,30),rand(0,21),rand(20,40),rand(0,21),$li);

}

//字符在图片的位置;

imagestring($im,5,8,2,$authnum_session,$white);

for($i=0;$i<90;$i++)

{//加入干扰象素

imagesetpixel($im,rand()%70,rand()%30,$gray);

}

ImagePNG($im);

ImageDestroy($im);

?>

中文

<?php

/*

*文件:code.php

*作用:验证码生成

*/

session_start();

//设置content-type

header("Content-type:image/png");

//创建图片

$im=imagecreatetruecolor(120,30);

$ChineseChar=array("人","出","来","友","学","孝","仁","义","礼","廉","忠","国","中","易","白","者","火","土","金","木","雷","风","龙","虎","天","地",

"生","晕","菜","鸟","田","三","百","钱","福","爱","情","兽","虫","鱼","九","网","新","度","哎","唉","啊","哦","仪","老","少","日",

"月","星");

//创建颜色

$fontcolor=imagecolorallocate($im,255,255,255);

$bg=imagecolorallocate($im,0,0,0);

//设置文字

for($i=0;$i<4;$i++)$text.=$ChineseChar[(array_rand($ChineseChar))];

$_SESSION['code']=$text;

//设置字体[url]http://www.font.com.cn/downlist/s_12_3.html[/url]有_GBK系列的字体下载,一般GD库都支持的!

$font='gbk.ttf';

//添加文字

imagettftext($im,18,0,11,21,$fontcolor,$font,iconv("GB2312","UTF-8",$text));

//输出图片

imagepng($im);

imagedestroy($im);

?>