Floating point number in JavaScript
JavaScript’s Number type, which is essentially IEEE 754 basic 64-bit binary floating-point, has 53-bit significands. 52 bits are encoded in the “trailing significand” field. The leading bit is encoded via the exponent field (an exponent field of 1-2046 means the leading bit is one, an exponent field of 0 means the leading bit is zero, and an exponent field of 2047 is used for infinity or NaN).