javascript - Object creation in loop broken; unrolled works

Question

I'm doing some testing and ran into this bizarre situation: The first case (assigning objects like InfoWindows in a loop) does not work as expected, while writing the assignments one by one does work.

The expected behavior is for an InfoWindow to open when the mouse is over a marker. Many windows should stay open at the same time.

Superficially, I don't see any difference. What's going on? I'm showing relevant code and a full JSFiddle for each case.

Does not work JSFiddle

    iwArray = [];
    for (var i = 0; i < 3; i++) {
      iwArray[i] = new google.maps.InfoWindow({content: "w "});
      google.maps.event.addListener(marker[i], 'mouseover', function(e) {
        iwArray[i].open(map, this);
      });
    }

Works, but is ugly JSFiddle

    iwArray = [];

    iwArray[0] = new google.maps.InfoWindow({content: "w 0"});
    google.maps.event.addListener(marker[0], 'mouseover', function(e) {
      iwArray[0].open(map, this);
    });

    iwArray[1] = new google.maps.InfoWindow({content: "w 1"});
    google.maps.event.addListener(marker[1], 'mouseover', function(e) {   
      iwArray[1].open(map, marker[1]);
    });

    iwArray[2] = new google.maps.InfoWindow({content: "w 2"});
    google.maps.event.addListener(marker[2], 'mouseover', function(e) {
      iwArray[2].open(map, marker[2]);
    });

Answer 1

Use closure:

 for (var i = 0; i < 3; i++) {
    (function(i){
       iwArray[i] = new google.maps.InfoWindow({content: "w "});
       google.maps.event.addListener(marker[i], 'mouseover', function(e) {
          iwArray[i].open(map, this);
       });
    })(i);
}