Google地图中的框/矩形绘制选择

I am working on Google Maps and want to implement a feature where a user can draw a box/rectangle using his/her mouse to select a region on map (like selecting multiple files in windows). Upon selection, I want to get all the markers that fall in the region. I have been looking around both Google Maps api and search but I am unable to find a solution. I tried using jQuery Selectable for selection but all it returns is a bunch of divs from which I am unable to determine if any marker is selected or not. I am working on Google Maps and want to impleme