PHP File Formatting
Tags
PHP code must always being with the long form opening tag. If a file contains only PHP code, the end tag may optionally be omitted from the end of a file.
<?php ?>
Indentation
Tabs should always be used for indentation. Spaces should never be used for indentation. We live in a world where IDEs can be configured to display tabs at variable lengths, so configure your tab width to what you feel comfortable with.
Line Length
Lines should be designed such that a reader can avoid horizontal scrolling, except in cases where scrolling offers improved readability over word-wrapping. As the resolution and width of monitors has increased the standard with of 80 characters (previously the width of a punch card) no longer holds any relevance. Use your best judgement to determine where lines should wrap.
EOL
Every line should terminate with a line-feed (LF) character only. That is '\n', also known as hex value 0x0A. Do not use CRLF (Window systems) or CR (Mac systems).
Character Encoding
All PHP files should be encoded using UTF-8, with no byte-order-mark (BOM).