本文實(shí)例為大家分享了幾段php驗(yàn)證碼函數(shù)，都很實(shí)用，具體內(nèi)容如下
代碼段一：簡(jiǎn)單php驗(yàn)證碼函數(shù)
<?php
function code(){
$im = imagecreatetruecolor(100, 40);
$black = imagecolorallocate($im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);
imagefill($im,0,0,$white);
$strarr=array_merge(range(0,9),range(a,z),range(A,Z));
shuffle($strarr);
$str=join(array_slice($strarr,0,4));
$mm=rand(0,40);
$aaa=rand(0,0);
$bbb=rand(0,255);
$ccc=rand(0,255);
$color1=imagecolorallocate($im,$aaa,$bbb,$ccc);
imagestring($im,5,$mm,10,$str,$color1);
for($i=0;$i<700;$i++){
$aa=rand(0,255);
$bb=rand(0,255);
$cc=rand(0,255);
$color=imagecolorallocate($im,$aa,$bb,$cc);
$a=rand(0,100);
$b=rand(0,40);
imagesetpixel($im,$a,$b,$color);
}
for($t=0;$t<3;$t++){
$a1=rand(0,255);
$b1=rand(0,255);
$c1=rand(0,255);
$color2=imagecolorallocate($im,$a1,$b1,$c1);
$a2=rand(0,100);
$b2=rand(0,40);
$a3=rand(0,100);
$b3=rand(0,40);
imageline($im,$a2,$b2,$b3,$b3,$color2);
}
header("content-type:image/png");
imagepng($im);
}
code() ;
?>
代碼段二：php驗(yàn)證碼函數(shù)
function _code($_code_length = 4, $_width = 75, $_height = 25){
for($i=0;$i<$_code_length;$i++){
$_nmsg .= dechex(mt_rand(0,15));
}
$_SESSION["code"] = $_nmsg;
$_img = imagecreatetruecolor($_width, $_height);
$_white = imagecolorallocate($_img, 250, 250, 250);
imagefill($_img, 0, 0, $_white);
$_gray = imagecolorallocate($_img, 196, 196, 196);
imagerectangle($_img, 0, 0, $_width-1, $_height-1, $_gray);
for ($i=0; $i < 6; $i++) {
$_md_color = imagecolorallocate($_img, mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));
imageline($_img, mt_rand(0,$_width), mt_rand(0, $_height),mt_rand(0,$_width), mt_rand(0, $_height), $_md_color);
}
for ($i=0; $i < 50; $i++) {
$_md_color = imagecolorallocate($_img, mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));
imagestring($_img, 1, mt_rand(1,$_width-5), mt_rand(1, $_height-5), "*", $_md_color);
}
for ($i=0; $i < $_code_length ; $i++) {
$_md_color = imagecolorallocate($_img, mt_rand(0,102), mt_rand(0,102), mt_rand(0,102));
imagestring($_img, 5, $i * $_width/$_code_length+ mt_rand(1, 10), mt_rand(1, $_height/2), $_SESSION["code"][$i], $_md_color);
}
header("Content-Type:image/png");
imagepng($_img);
imagedestroy($_img);
}
代碼段三：php圖片驗(yàn)證碼函數(shù)
/*@ captcha()函數(shù)的功能：生成驗(yàn)證碼
* @ 可自定義參數(shù)：
* @ $width 圖片寬度，默認(rèn)80
* @ $high 高度，默認(rèn)25
* @ $num 驗(yàn)證碼個(gè)數(shù)，默認(rèn)4個(gè)
* @ $line_num 隨機(jī)畫線條的個(gè)數(shù)，默認(rèn)10
* @ $snow_num 隨機(jī)雪花的數(shù)量，默認(rèn)50
*/
function captcha($width=80,$high=25,$num=4,$line_num=10,$snow_num=50){
header('Content-Type:image/png');
session_start();
//生成隨機(jī)數(shù)字＋字母
for($a = 0;$a < $num;$a++){
$code .= dechex(mt_rand(0, 15));//dechex — 十進(jìn)制轉(zhuǎn)換為十六進(jìn)制
}
//把生成的驗(yàn)證碼保存在SESSION超級(jí)全局?jǐn)?shù)組中
$_SESSION['captcha'] = $code;
//創(chuàng)建畫布
$img = imagecreatetruecolor($width,$high);
//填充背景色為白色
$backcolor = imagecolorallocate($img, '255', '255', '255');
imagefill($img, '0', '0', $backcolor);
//添加黑色邊框
$bordercolor = imagecolorallocate($img, 0, 0, 0);
imagerectangle($img, 0, 0, $width-1, $high-1, $bordercolor);
//隨機(jī)畫線條
for($i=0;$i<$line_num;$i++){
imageline($img, mt_rand(0, $width*0.1), mt_rand(0, $high), mt_rand($width*0.9, $width), mt_rand(0, $high),
imagecolorallocate($img, mt_rand(150, 255), mt_rand(150, 255), mt_rand(150, 255)));
}
//隨機(jī)打雪花
for ($i=0;$i<$snow_num;$i++){
imagechar($img,1, mt_rand(0, $width), mt_rand(0, $high),'*',
imagecolorallocate($img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255)));
}
//畫驗(yàn)證碼
for ($b = 0;$b < strlen($_SESSION['captcha']);$b++){
imagechar($img,5, $b*$width/$num+mt_rand(5,10), mt_rand(2, $high/2),$_SESSION['captcha'][$b],
imagecolorallocate($img, mt_rand(10, 150), mt_rand(10, 150), mt_rand(0, 100)));
}
ob_clean();//清空輸出緩沖區(qū)
imagepng($img);
imagedestroy($img);
}
以上就是三段參考性較高的php驗(yàn)證碼函數(shù)，希望對(duì)大家學(xué)習(xí)php程序設(shè)計(jì)有所幫助。