图形数字验证代码 Code:   <? /* * Filename: authpage.php */ srand((double)microtime()*1000000); //验证用户输入是否和验证码一致 if(isset($_POST['authinput'])) { if(strcmp($_POST['authnum'],$_POST['authinput'])==0) echo "验证成功！"; else echo "验证失败！"; } //生成新的四位整数验证码 while(($authnum=rand()000)<1000); ?> <form action=authpage.php method=post> <table> 请输入验证码：<input type=text name=authinput style="width: 80px"><br> <input type=submit name="验证" value="提交验证码"> <input type=hidden name=authnum value=<? echo $authnum; ?>> <img src=authimg.php?authnum=<? echo $authnum; ?>> </table> </form> ------------------------------------------------------------------------------------------------------------- <? /* * Filename: authimg.php */ //生成验证码图片 Header("Content-type: image/PNG"); srand((double)microtime()*1000000); $im = imagecreate(58,28); $black = ImageColorAllocate($im, 0,0,0); $white = ImageColorAllocate($im, 255,255,255); $gray = ImageColorAllocate($im, 200,200,200); imagefill($im,68,30,$gray); //将四位整数验证码绘入图片 imagestring($im, 5, 10, 8, $HTTP_GET_VARS['authnum'], $white); for($i=0;$i<50;$i++) //加入干扰象素 { imagesetpixel($im, rand()%70 , rand()%30 , $gray); } ImagePNG($im); ImageDestroy($im); ?>