例子：有序数组查找
//1递归做法
function findArr(arr,value,left,right){
var mid=Math.floor((left+right)/2);
//防止无穷递归
if(left>right){
return
}
if(arr[mid]>value){//左边
return findArr(arr,value,left,mid-1)
}else if(arr[mid]<value){//右边
return findArr(arr,value,mid+1,right)
}else{
return ‘找到了，位置是‘+mid;
}
};
//2 二进制做法
function binary(items,value,startIndex,stopIndex){
var middleIndex=(startIndex+stopIndex)>>>1;
while(items[middleIndex]!=value && startIndex<stopIndex){
if(items[middleIndex]>value){
stopIndex=middleIndex-1;
}else{
startIndex=middleIndex+1;
}
middleIndex=(startIndex+stopIndex)>>>1;
}
return items[middleIndex]!=value ? false:middleIndex;
}
var arr=[11,22,33,44,55,66,77,88,99];
alert(findArr(arr,66,0,arr.length-1));
alert(binary(arr,660,arr.length-1));
原文：http://www.cnblogs.com/parry-font/p/4024168.html