Hey, octothorp/octothorpe/octotherp was around for many many years before programmers ever started calling it the "hash symbol". It never had been in usage in the USA before you Brits started calling it that.
It was actually called the "pound sign" when I was a kid, meaning weight in pounds (you know, those things you Brits invented, foisted off on us, and then abandoned!). That is, we used to commonly write 37# (pr sometimes #37) meaning 16.8kg.
Anyway, I started programming in the 1960s, so octothorp is appropriate for me!
http://en.wiktionary.org/wiki/octothorpe
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So far as I am concerned, JavaScript is useless without completely understanding HTML and CSS. You will keep on asking questions like this because even JavaScript programmers *NEED* to know how the underlying HTML and CSS work to be effective. You are running around with blinders on (or that another Americanism?) if you fail to learn HTML and CSS.