<div id="mydiv"></div>

<script>

// 函数：从大到小排列数组
let sort2small = (a,b) => b - a;

//函数：中间大两头小排列数组
let resortAr = (arr) => {
	let new_ar = [];
	arr.sort(sort2small);
	// 遍历数组元素，依据j被2整除与否将arr数组元素往前或往后塞入new_ar
	for(let j = 0; j < arr.length; j ++) {
		j % 2 === 0 ? new_ar.unshift(arr[j]) : new_ar.push(arr[j]);
	}
	return new_ar;
};

let ar = [2,41,5,87,8,23,0,9,15];
mydiv.innerText = '原数组：' + ar + '\n排序后：' + resortAr(ar);

</script>