JavaScript插入排序

function charu(arr) {
	var len = arr.length;
	var preIndex, current;
	for (var i = 1; i < len; i++) {
		preIndex = i - 1;
		current = arr[i];
		while (preIndex >= 0 && arr[preIndex] > current) {
			arr[preIndex + 1] = arr[preIndex];
			preIndex--;
		}
		arr[preIndex + 1] = current;
	}
	return arr;
}
console.log(charu([2, 4, 6, 56, 7, 8, 9]));