PHP, XML, Javascript... Which to learn first?

I’d like to start learning these languages.
One at a time, tho.

I know Javascript is Client-side, but anywho…

Which to learn first?

I already know HTML, CSS, a bit of SQL… And these are the ones that could be used online.
Offline I know Pascal, C, and in theory Visual Basic… Although that last one I could make no promise on realisticly knowing it. School tought and bad grades and the like…

Surprisingly! I just noticed I ordered the languages by how much I know them.

I do have a book on XML, but that doesn’t mean it’s any good, or that I should learn that first. Have a book on PHP and loads of others that don’t necessarily make it a good idea to learn first.

Got books on Basic, that belonged to my dad; and those aren’t a real good idea to spend any time on either.

So ye of more experience that I!
Where should I start?

I like AJAX, but don’t really understand the important languages used by it!