jQuery Forum

Hello

I'm playing around with reading the value.length of textarea's. Everything works fine, as long you're not using linebreaks.. and there it starts..


First of all, my environment details

OS:        Windows XP SP3
Browser:    IE 7.0.5730.13 (standards compliant rendering mode), Firefox 3.5.5
Doctype:    XHTML-Strict


Some facts

OS:

Windows is using by default 2 bytes for a linebreak
Unix is using by default 1 byte for a linebreak
Mac is using by default 1 byte for a linebreak

http://en.wikipedia.org/wiki/Newline


JavaScript:

As far as I know JavaScript is using only 1 byte for a linebreak (\n). Doesn't matter if it's running on a Windows/Unix/Mac OS.


HTTP/1.1 protocol:

HTTP/1.1 uses 2 bytes for a linebreak, if I understand correctly..

"HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all protocol elements except the entity-body..."

http://www.rfc-editor.org/rfc/rfc2616.txt


Tests

I have a form and within, there is a textarea element. I write the following text into it (without the start and end lines):

-- start
a
b
c
-- end

The following happens..

1. $textarea = $("textarea");
2. alert($textarea.val().length);        // 1. Will alert 5
3. alert($textarea[0].value.length);    // 2. Will alert 7

After my "investigations" I realized, this behavior is caused by the difference between how many bytes are used for a linebreak.

On a linux system with any browser the 2. statement will also return 5 (because unix uses only 1 byte for a linebreak).
But if I submit the form to the server, and check the length of the data of the textarea, it will tell me the string is 7 chars long (because http/1.1 uses 2 bytes per linebreak I guess).

Unfortunately I was not able to test it on a Mac.


Conclusion

I think it would be nice if the length property would return the correct value.. especially if you want to make some validation on a form/textarea.

Since http/1.1 protocol always converts 1 byte linebreaks to 2 bytes, we could assume that the webserver is always receiving 2 bytes for a linebreak. So also 2 bytes would be written to the database ( I hope I'm not telling bullshit here! :)

My solution at the moment is the following function:

1. if (String.prototype.realLength == undefined) {
2.     String.prototype.realLength = function() {
3.         var regex
4.         if (regexp.test(this)) {
5.             do { matchCount++; } while (regexp.exec(this));
6.             return this.replace(/\n|\r/g, "").length + matchCount * 2;
7.         }
8.         return this.length;
9.     };
10. }

Maybe there are better/different solutions, or maybe I made a mistake during my "investigations".

Please let me know..

Cheers, delijah