返回一个数组被截断n个元素后还剩余的元素，截断从索引0开始。
function slasher(arr, howMany) {// it doesn't always pay to be firstvar l=arr.length;var arr1=[];if(l<howMany){ return [];}else if(howMany===0){ return arr;}else{for(var i=0;i<howMany;i++)arr.splice(0,1);}return arr;
}slasher([1, 2, 3], 2);