Why is 9999999999999999 converted to 10000000000000000 in JavaScript?

Question

Can any one explain to me why 9999999999999999 is converted to 10000000000000000?

alert(9999999999999999); //10000000000000000

http://jsfid

Answer 1

1. JavaScript only has floating point numbers, no integers.

2. Read What Every Computer Scientist Should Know About Floating-Point Arithmetic.

   Summary: floating point numbers include only limited precision, more than 15 digits (or so) and you'll get rounding.