Find the largest element in a numeric array (using the Math.max function) __ function

Sample arrays:

var narray=[4002,1,5,99,2,1001,2335,9,20,48,3001,520,6666];

The following methods can be used in browsers that support the array reduce method

function Getmax (arrays) {
			var max = arrays.reduce (function (pre,cur,index,array) {return
				Math.max (pre,cur);
			});
			document.write (max);
		}

Normal browsers can be implemented using the push and pop methods of arrays. Efficiency, I hope you will correct me. (assuming that the array length is greater than 1)

function Getmax (arrays) {
			Arrays.push (Math.max (Arrays.pop (), Arrays.pop ()));
			if (arrays.length>1) {
				getmax (arrays);
			}
			else{
				document.write (arrays[0]);
			}