why chr() function at the end of echo

Question

I've found this line in one of the codes coppied from web but have no ide why they use char() function at the end of it. Please let me know why it is used, what it does and what if I don't use it all.

Thanks in advance.

CODE:

$crlf = chr(13) . chr(10);

echo '<html><head><title>Whatever</title></head><body>Hello</body></html>' . $crlf;

They are not using char at the end of it, they are using whatever the function returns, in this case it would be: the CarriageReturn (\r) and LineFeed(\n) in this case (a new line) — aleation, Jun 13 '13 at 14:36
@TerrySeidler `PHP_EOL` is platform related, so if you had a website on windows and then ported it to linux you could encounter some problems later on. — HamZa, Jun 13 '13 at 14:38
`PHP_EOL` *should* be platform-independent as far as I know: http://stackoverflow.com/questions/128560/when-do-i-use-the-php-constant-php-eol — Terry Seidler, Jun 13 '13 at 14:39
@TerrySeidler What I mean is the following, if you wrote `PHP_EOL` to a file, and later on you used `explode("\r\n", $data);` on windows it would work fine, but if you then go on linux, `PHP_EOL` will not use `\r\n`. — HamZa, Jun 13 '13 at 14:41

score 6 · Accepted Answer · edited Jun 13 '13 at 14:38

6

chr(13) is equivalent to "\r" and chr(10) is equivalent to "\n".

So, $crlf = chr(13) . chr(10); is a string containing "\r\n", a CRLF (newline) as the variable name states.

edited Jun 13 '13 at 14:38

Jacob Krall

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answered Jun 13 '13 at 14:36

gen_Eric

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@Jacob: Thanks, I'm a little lysdexic sometimes :) – gen_Eric Jun 13 '13 at 14:39

score 2 · Answer 2 · edited May 23 '17 at 10:28

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chr(13) and chr(10) return the ASCII representations of "Carriage return" and "Line feed". These characters can also be written as "\r\n" in PHP. On a Windows system, CR+LF together represent a newline. (See What is the difference between \r and \n?)

edited May 23 '17 at 10:28

Community

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answered Jun 13 '13 at 14:37

Jacob Krall

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score 0 · Answer 3 · answered Jun 13 '13 at 14:35

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The "chr()" function returns a specific ASCII value. See php chr function and ascii chart - Which should help you understand more :)

answered Jun 13 '13 at 14:35

fantasitcalbeast

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score 0 · Answer 4 · answered Jun 13 '13 at 15:09

The questioner asked

Please let me know why it is used, what it does and what if I don't use it all.

And I don't think anybody answered that yet ...

The programmer is presumably trying to format the HTML code of the page so that is is more readable when displayed through a browser's 'view source' functionality. So the $crlf could be omitted safely, so long as you don't care what the HTML source looks like.

Seems an odd decision to use two function calls rather than typing "\r\n", but who knows, the coder may have had his/her reasons.

why chr() function at the end of echo

4 Answers4