How do you find the min and max values without Math functions

You can write functions which loop through an array comparing each value with the lowest value or highest value to find the min and max values. Let's create those functions to find min and max values,

var marks = [50, 20, 70, 60, 45, 30];
function findMin(arr) {
var length = arr.length;
var min = Infinity;
while (length--) {
if (arr[length] < min) {
min = arr[length];
}
}
return min;
}

function findMax(arr) {
var length = arr.length;
var max = -Infinity;
while (length--) {
if (arr[length] > max) {
max = arr[length];
}
}
return max;
}

console.log(findMin(marks));
console.log(findMax(marks));