EA javascript - Calculate log() base 10?

I am writing an algorithm to calculate the top value and ticks on the Y axis of a dynamic chart.

To do the calculation the cleanest way, I need to be able to calculate a log() with a base 10.

JavaScript has both a log base 10 function - Math.log10() - and a constant - Math.LN10 - and a way that log can be calculated for any base - Math.log(num, base). Sadly, none of these seem to work in Edge Animate CC's version of javascript.

Can someone tell me how to get the log of a number in base 10 in Edge Animate CC?

TIA,

Carolyn