用这些代码怎么判断一个验证码呢
<form name="form1" method="post" action="">
<input name="text" type="text" id="text" size="8">
<?php
header("Content-type: image/png");
$im = @imagecreate(34, 16) or die("Cannot Initialize new GD image stream");
$bc = imagecolorallocate($im,rand(300,4000),rand(200,5000),rand(255,900));
$tc = imagecolorallocate($im,rand(300,9000),rand(2000,500),rand(799,3000));
$namea=rand(5001,2000);
echo $$namea
imagestring($im, 2, 3, 3,$namea, $tc);
for($i=0;$i<50;$i++) //加入干扰象素
{
imagesetpixel($im, rand(200,3000), rand(2000,500) ,$bc);
}
ImagePNG($im,"im.png");
ImageDestroy($im);
?>
<img src="im.png" size="8" name="namename">
<input type="submit" name="Submitqw" value="提交"></form>