编写一个函数,把一个数组arr按照指定的数组大小size分割成若干个数组块。

例如:chunk([1,2,3,4],2)=[[1,2],[3,4]];

chunk([1,2,3,4,5],2)=[[1,2],[3,4],[5]];

function chunk(arr, size) {
    var arr1=new Array();
	for (var i = 0; i < Math.ceil(arr.length/size); i++) {
	   arr1[i]=new Array();
	}
	var j=0;
	var x=0;
	for (var i = 0; i < arr.length; i++) {
		if(!((i%size==0)&&(i!=0))){
			arr1[j][x]=arr[i];
			x++;
			console.log("j="+j+"  "+"x="+x);
		}else{
			j++;
			x=0;
			console.log("else:"+"j="+j+"  "+"x="+x);
			arr1[j][x]=arr[i];
			console.log(arr1);
			x++;
		}
	}
	return arr1;
}
chunk(["a", "b", "c", "d"], 2);