Chapter 21
JavaScript Reference

Math.log() Function

Name

Math.log() Function---compute a natural logarithm

Navigator 2.0, Internet Explorer 3.0

Math.log(x)

The natural logarithm of x.

Math.log() computes log_ex, the natural logarithm of its argument. The argument must be greater than zero.

You can compute the base-10 and base-2 logarithms of a number with the following formulas:

log₁₀x = log₁₀(e*log_ex)

log₂x = log₂(e*log_ex)

These formulas translate into the following JavaScript functions:

function log10(x) { return Math.LOG10E * Math.log(x); }
function log2(x) { return  Math.LOG2E * Math.log(x); }