function foo(x)
    {
    return x * x;
    }

function removeKeyFrames(property)
    {
    var numKeys = property.numKeys;
    var i;

    for(i = 1; i <= numKeys; i++)
        {
        property.removeKey(1);
        }
    }

myComp = app.project.activeItem;
if(!(myComp instanceof CompItem))
    {
    alert("please select a composition.");
    }
else
    {
    app.beginUndoGroup("crossfade the layers");

    var myLayers = myComp.layers;

    var m = myComp.name + " layers: ";
    for(i = 1; i <= myLayers.length; i++)
        {
        m += myLayers[i].name + ",";
        }

    alert(m);

    var fadeTime = .2;
    var holdTime = 1.7;
    var t = 0; 
    for(i = 1; i <= myLayers.length; i++)
        {
        l = myLayers[i];
        l.startTime = t;
        l.inPoint = t + 0;
        l.outPoint = t + holdTime + 2 * fadeTime;

        var o = l.property("opacity");
        removeKeyFrames(o);
        if(fadeTime)
            o.setValueAtTime(t,0);
        o.setValueAtTime(t + fadeTime,100);
        o.setValueAtTime(t + fadeTime + holdTime,100);
        if(fadeTime)
            o.setValueAtTime(t + fadeTime + holdTime + fadeTime,0);

        //var o = l.property("scale");
        //removeKeyFrames(o);
        //o.setValueAtTime(t,[120,120]);
        //o.setValueAtTime(t + fadeTime + holdTime + fadeTime,[100,100]);

        t += fadeTime + holdTime;
        }

    app.endUndoGroup();
    }