PHP output buffer is not empty?

Question

I have this peculiar problem. I am making an AJAX call to a PHP page. In case of error I am returning the string "error" to success: function(msg) ie msg will have the value "error". But for some reason it is sending back "error" but with a line break preceding it. And this fails the condition when i check if (msg=="error") . I have to put ob_clean() to clear out the output buffer. Then it returns "error" without line break. I checked but my PHP function is not outputting anything before the "error". What can be the issue that the output buffer is not empty?

Answer 1

That happens because some of your php files has an empty line before <?php or after ?>

As PhpMyCoder propsed - you could also not put ?> in the end of the file at all. Php allows doing that.