The base ten logarithm. Gives the number of digits in the number before the decimal point. On zero, returns -inf. Below zero, returns NaN, a special value that always causes failure when compared to other numbers. (ie. (NaN<0) -> false, (NaN>=0) -> false)<br/> other logarithms<br/> log10(x) = log(x, 10)<br/> log10(x)/log10(e) = ln(x)<br/> log10(2)=0.3010-ish<br/> log10(e)=0.4343-ish<br/> log10(10)=1<br/>

trace(log10(1))  # prints '0' 
trace(log10(10)) # prints '1'