29th June 2008 under What I think

When PHP goes BOM! on Internet Explorer

I was recently working on a web content management system with a friend and we made a very surprising discovery. We were actually using PHP to include content from another page on our local server unto the page that was curently being viewed. This thing worked perfectly when I was using the Eclipse editor but when I moved to my friends office and we started using Expression studio (which obviously doesn't seem to support PHP), the include statement started introducing unwanted characters. Although most of the browsers on which this was tested (Opera, Safari and FireFox) skipped these characters, IE of all browsers displayed them and messed up our template. Well we started to panic because we didn't know what we had done wrong and IE is one browser you don't want to mess with because everybody uses it.

So we started digging on the Internet to find out what was actually wrong with the system. The first hint of our real problem was sensed when we saw a large number of newsgroup posts which described problems similar to what we were facing. Then we realized we were actually playing around with encoding problems. We figured out that saving the files we wanted to include with ANSI encoding saved the day.

The previous encoding format we were using was the UTF-8 format. This format is preceeded with a Byte Order Mark (BOM). This Byte Order Mark is obviously supposed to tell the reader of the format about the byte order of the file it is reading. When the PHP include function was called to include this file it also included the BOM characters which IE decided to display and mess up the template.