最簡單的php驗證碼

標籤：驗證碼

<?phpsession_start();$nums = "";for($i=0;$i<4;$i++){//產生隨機數並轉換成十六進位$nums.=dechex(mt_rand(0,15));}//將驗證碼寫入session$_SESSION[‘code‘]=$nums;//設定驗證碼長和寬$_width = 60;$_height = 20;//建立一張圖片$_img = imagecreatetruecolor($_width,$_height);//建立一個白色$_white = imagecolorallocate($_img,220,250,250);//填充背景imagefill($_img,0,0,$_white);//隨機線條for($i=0;$i<8;$i++){$_rnd_color = imagecolorallocate($_img,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));imageline($_img,mt_rand(0,$_width),mt_rand(0,$_width),mt_rand(0,$_width),mt_rand(0,$_width),$_rnd_color);}//隨機雪花for($i=0;$i<80;$i++){imagestring($_img,1,mt_rand(1,$_width),mt_rand(1,$_height),"*",imagecolorallocate($_img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255)));}//輸出驗證碼for($i=0;$i<strlen($_SESSION[‘code‘]);$i++){imagestring($_img,mt_rand(6,10),$i*$_width/4+mt_rand(1,10),mt_rand($_height/6,$_height/4),$_SESSION[‘code‘][$i],imagecolorallocate($_img,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)));}//輸出和銷毀header("Content-Type:image/png");imagepng($_img);imagedestroy($_img);?>

最簡單的php驗證碼