javascript 二分法（数组阵列）

Array.prototype.binarySearch = function(obj)
{
var value = 0;
var left = 0;
var right= this.length;
while(left <= right)
{
var center = Math.floor((left+right)/2);
if(this[center] == obj)
{
value = center;
}
if(obj < this[center])
{
right = center - 1;
}
else
{
left = center + 1;
}
}
alert(value);
}
//如下为测试代码：
function testArrayBinarySearch()
{
var array = new Array();
var key = 678;
var number = 1000;
for (i = 0; i < number; i++)
{
array.push(i);
}
array.binarySearch(key);
}
window.onload = function()
{
testArrayBinarySearch();
}