var array = [2,1,5,4,8,99,3,7];
var arrlength = array.length;

for(var i = 0; i < arrlength; i++) {

	pos = i
	valor = array[i]

	while(pos > 0 && valor < array[pos - 1]){
		array[pos] = array[pos - 1]
		pos = pos - 1
	}

	array[pos] = valor

}

console.log(array)