var grow = false;

function CanvasLoaded(sender, args)
{
    var storyboard = getXamlElement("wpfeControl1", "grow");    
    storyboard.Begin();
}
function StoryboardCompleted(sender, args)
{    
    sender.Stop();
    
    grow = !grow;
    
    var start = grow ? "shrink" : "grow";
    
    var startSb = getXamlElement("wpfeControl1", start);       
    
    startSb.Begin(); 
}