Q:

Why does JavaScript use base 10 floating point numbers (according to w3schools)?

I read this on W3Schools:

All numbers in JavaScript are stored as 64-bit (8-bytes) base 10,
  floating point numbers.

This sounds quite strange. Now, it's either wrong or there should be a good reason not to use base 2 like the IEEE standard.
I tried to find a real JavaScript definition, but I couldn't find any. Either on the V8 or WebKit documentation, the two JavaScript implementation I could find on Wikipedia that sounded the most familiar to me, I could find how they stored the JavaScript Number type.
So, does JavaScript use base 10? If so, why? The only reason I could come up with was that maybe using base 10 has an advantage when you want to be able to accurately store integers as well as floating point numbers, but I don't know how using base 10 would have an advantage for that myself.

A:

That's not the World Wide Web Consortium (W3C), that's w3schools, a website that isn't any authority for any web standards.
Numbers in Javascript are double precision floating point numbers, following the IEEE standards.
The site got the part about every number is a 64-bit floating point number right. The base 10 has nothing with the numerical representation to do, that probably comes from the fact that floating point numbers are always parsed and formatted using base 10.

A:

Numbers in JavaScript are, according to the ECMA-262 Standard (ECMAScript 5.1) section 4.3.19:

Primitive values corresponding to a double-precision 64-bit binary format IEEE 754 value.

Thus, any implementation using base 10 floating point numbers is not ECMA-262 conformant.

A:

JavaScript uses, like most modern languages, IEEE754. Which isn't at all stored in base 10.
The specificity of JavaScript is that there is only one number type, which is the double precision float. Which has the side effect that you're somewhat limited contrary to other languages if you want to deal with integers : you can't store any double precision integer, only the ones fitting in the size of the fraction (52 bits).

