Useragent check with 'strlen' and 'strstr'

Question

I am testing this code but "hello" gets shown in every browser. Normally it should only show up in MSIE.

Did I forgot something?

   $usragent = $_SERVER['HTTP_USER_AGENT'];

    echo $usragent;

    if(
    ((strlen(strstr($usragent,"Firefox")) <= 0)) || 
    ((strlen(strstr($usragent,"Chrome")) <= 0)) ||
    ((strlen(strstr($usragent,"Safari")) <= 0))
        )
        {
        echo "hello";
        }

@AndyLester I use the code from this question. but it is not working — Mike, Oct 13 '13 at 19:32
change your || to && , in order to print hello for anything other than what you are checking (Firefox, Chrome, Safari) — melc, Oct 13 '13 at 19:36

score -1 · Answer 1 · answered Oct 13 '13 at 19:37

-1

I suggest using the php function strpos. Example:

if (strpos($usragent,'MSIE') == true) {
    echo 'hello';
}

To complete your case, example:

if (strpos($usragent,'Firefox') || strpos($usragent,'Chrome') || strpos($usragent,'Safari')) {
    echo "hello";
}

answered Oct 13 '13 at 19:37

Arjen

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You fail to recognize that `strpos()` returns the position of the found string, which can be zero if it is at the start. That zero will evaluate to false when compared with true, and your code will give wrong results. Always compare strictly with false! `if (strpos() !== false) { echo "found";}` – Sven Oct 13 '13 at 19:57

Useragent check with 'strlen' and 'strstr'

1 Answers1