How to sort an array of integers correctly

Question

Trying to retrieve the greatest and lowest values from an array that I know would only include numbers appears to be more difficult than I anticipated.

var numArray = [140000, 104, 99];
numArray = numArray.sort();
console.log(numArray)

This should display 99, 104, 140000. Instead, it displays 104, 140000, and 99. So it appears that the sort is treating the data as strings.

Is there a method to have the sort function sort on integer values?