<script type="text/javascript">
//将数组头部的一个集合移动到数组末尾，不允许使用数组自带的方法
//{1,2,3,4,5,6,7}=>{4,5,6,7,1,2,3}
var arr = ['num-1','num-2','num-3','num-4','num-5','num-6','num-7'];
function moveHeadCollectToEnd1(arr,pos){
for(var i=0;i<=pos;i++){
var temp = arr[0];
for(j=0;j<arr.length-1;j++){
arr[j] = arr[j+1];
}
arr[arr.length-1] = temp;
}
}
function moveHeadCollectToEnd2(arr,pos){
var diff = (pos/2)|0;
var temp;
for(var i=0;i<=diff;i++){
temp = arr[i];
arr[i] = arr[pos-i];
arr[pos-i] = temp;
}
diff = (arr.length-1-pos)/2;
for(i=0;i<=diff;i++){
temp = arr[pos+1+i];
arr[pos+1+i] = arr[arr.length-1-i];
arr[arr.length-1-i] = temp;
}
diff = ((arr.length-1)/2)|0;
for(i=0;i<=diff;i++){
temp = arr[i];
arr[i] = arr[arr.length-1-i];
arr[arr.length-1-i] = temp;
}
}
moveHeadCollectToEnd1(arr,2);
//moveHeadCollectToEnd2(arr,2);
alert(arr);
// 两种方法 2的方法效率要高于1
</script>