help with isolated php failure

This is a spin-off of my other thread. I've got some code php code that determines the browser and then gives you different output according to the browser. Here's the code:

Quote:

<?

{ global $HTTP_USER_AGENT;
if(strstr($HTTP_USER_AGENT, "MSIE 6")) {
$check = "good";
$browser = "MSIE6";} // MSIE6
else if(strstr($HTTP_USER_AGENT, "MSIE 5")){
$check = "good";
$browser = "MSIE5";} // MSIE5
else if(strstr($HTTP_USER_AGENT, "MSIE 4")){
$check = "bad";
$browser = "MSIE";} // MSIE4
else if(strstr($HTTP_USER_AGENT, "Netscape6")){
$check = "good";
$browser = "NS6";} // NS6
else if(strstr($HTTP_USER_AGENT, "Mozilla/4")){
$check = "bad";
$browser = "NS4";} // NS4
else if(strstr($HTTP_USER_AGENT, "Mozilla/5")){
$check = "bad";
$browser = "Mozilla";} // Mozilla
else if(strstr($HTTP_USER_AGENT, "Opera/6")){
$check = "bad";
$browser = "Opera";} // Opera
else {
$check = "bad";
$browser = "Unknown";} // Unknown
};

print "Browser Check:".$check;

print "Browser Type:".$browser;

if ($check = "good") {
print "this is a print of a good output";
} else {
print "this is a print of a bad output";
}

?>

When using NS4.7, the first print line outputs that the browser check is "bad". That's correct. The next print line outputs that the browser type is NS4. This is also correct, but not really relevant. The next section says if the browser check is good, print the good output - and if anything else, print the bad output. Since we know that the browser check ($check) is working properly and comes up as "bad", why does my code function incorrectly and give you the good output that should only work if browser check was good? Any wierd failures should end up in the "else" section? What went wrong?

You can see the script work properly in MSIE5 but fail in NS4: mikesussman.com/2.php