\n vs. PHP_EOL vs. <br>?
newline, nl2br, php
Solution
DOS, Unix, and Mac (pre-OS X and OS X) all use different characters or character combinations to represent "go to the next line."
DOS - Uses a CR+LF (that's ASCII 13 followed by an ASCII 10, or `\r\n`) to represent a new line.
Unix - Uses an LF (that's ASCII 10, or `\n`) to represent a new line.
Mac (pre-OS X) - Uses a CR (that's ASCII 13, or `\r`) to represent a new line.
Mac (OS X) - Like Unix, uses an LF to represent a new line.
Therefore, when to use each one depends on what you're going for. If you're writing for a specific platform without the intention of portability, use the character or character combination to break lines that matter to that platform. The purpose of `PHP_EOL` is to automatically choose the correct character for the platform, so that your new lines are platform-independent.
All of these appear as a single space within a browser as browsers collapse whitespace into a display space for display purposes (unless you're using `<pre>` as you mentioned, or CSS that changes the behavior of whitespace). This is where `<br>` comes in, as you've mentioned, which will convert these `\n` new line characters into `<br>` so that they provide line breaks in HTML display.
Problem
In most cases, as for one interactive website, when we output multiple lines of contents to web client browser, in my opinion, `<BR />` is much more preferable than other two: `\n` or `PHP_EOL`. Else, we need to use "`<pre></pre>`" to wrap the output content or use `nl2br()` to insert `<BR />` before `\n` so as the multiple line mark can take effect in HTML. Like following example. ``` $fruits = array('a'=>'apple', 'b'=>'banana', 'c'=>'cranberry'); // Multiple lines by \n foreach( $fruits as $key => $value ){ echo "$key => $value \n" ; } // Multiple lines by PHP_EOL reset( $fruits ); while ( list($key, $value) = each( $fruits ) ){ echo ("$key => $value" . PHP_EOL); } // Multiple lines by <BR /> reset( $fruits ); while ( list($key, $value) = each( $fruits ) ){ echo ("$key => $value <BR />"); } ``` Some people believe `PHP_EOL` is useful when writing data to a file, example a log file. It will create line breaks no matter whatever your platform. Then, my question is when we use `\n`? What's the difference between `\n` and `PHP_EOL`, and `<BR />`? Could any body have a big list of each of their pros and cons?