d3.max = function(array, f) {var i = -1, n = array.length, a, b;if (arguments.length === 1) {//取数组中第一个非undefined数值while (++i < n && !((a = array[i]) != null && a <= a)) a = undefined;while (++i < n) if ((b = array[i]) != null && b > a) a = b;} else {while (++i < n && !((a = f.call(array, array[i], i)) != null && a <= a)) a = undefined;while (++i < n) if ((b = f.call(array, array[i], i)) != null && b > a) a = b;}return a;};