why do both lines of code work?!

Hello,

I have 2 lines of code which are different but both work. I refer to
the 3rd line with the url in it. In the first case the // are not
escaped, in the second they are.

Either

soundManager.createSound({
id:'mySound'+t,
url:'http://www.site.com/files/Track'
+ (+t+35) + '.mp3',
onfinish:function(){document.getElementById('test'+t+1).className =
'visibleDiv2'} });
soundManager.play('mySound'+t);
count++;

Or

soundManager.createSound({
id:'mySound'+t,
url:'http:\/\/www.site.com/files/Track' + (+t+35) + '.mp3',
onfinish:function(){document.getElementById('test'+t+1).className =
'visibleDiv2'} });
soundManager.play('mySound'+t);
count++;

The only difference as far as I can see is that with the 

url:'http://www.site.com/files/Track'
+ (+t+35) + '.mp3',

the part after http: to the end of the line is grayed out with
Homesite (my html editor) whereas with

url:'http:\/\/www.site.com/files/Track' + (+t+35) + '.mp3',

it is not.

Is there any other difference?! I am used to the idea of escaping
various characters but usually the "\" is required for the code to
work.

Cheers

Geoff