Math.log( x ) in ECMAScript 262

Return the natural logarithm of x.


x Number The value to operate upon.
Return Type


This function returns the natural logarithm of the argument; i.e. the log-base-e. Put another way, Math.pow(Math.E , Math.log( n ) ) == n. (Or more simply, Math.exp( Math.log(n) ) == n.)

To get the log-base-10 value of a number, use the fact that log-base-t( x ) == log-base-e(x) / log-base-e(t).

The following code will provide the Math class with a new convenience function for log-base-10:

Math.log10=function(x){ return Math.log(x)/Math.LN10 }

Or, for a more general case:

Math.logN=function(n,x){ return Math.log(x)/Math.log(n) }