How can I use a carriage return in a HTML tooltip?

The latest specification allows line feed character, so a simple line break inside the attribute or entity 
 (note that characters # and ; are required) are OK.


It’s so simple you’ll kick yourself: just press Enter!

<a href="#" title='Tool
Tip
On
New
Line'>link with tip</a>


Try character 10. It won't work in Firefox though. :(

The text is displayed (if at all) in a browser dependent manner. Small tooltips work on most browsers. Long tooltips and line breaking work in IE and Safari (use &#10; or &#13; for a new newline). Firefox and Opera do not support newlines. Firefox does not support long tooltips.

http://modp.com/wiki/htmltitletooltips

Update:

As of January 2015 Firefox does support using &#13; to insert a line break in an HTML title attribute. See the snippet example below.

<a href="#" title="Line 1&#13;Line 2&#13;Line 3">Hover for multi-line title</a>