var customFloatingObject = new GcSpread.Sheets.CustomFloatingObject("f1", 20, 20, 60, 64);
var btn = document.createElement('button');
btn.style.width = "60px";
btn.style.height = "30px";
btn.innerText = "button1";
customFloatingObject.Content(btn);
activeSheet.addFloatingObject(customFloatingObject);
var customFloatingObject1 = new GcSpread.Sheets.CustomFloatingObject("f2", 5, 5, 30, 64);
var btn1 = document.createElement('button');
btn1.style.width = "60px";
btn1.style.height = "30px";
btn1.innerText = "button2";
customFloatingObject1.Content(btn1);
activeSheet.addFloatingObject(customFloatingObject1);
var floating = activeSheet.getFloatingObjects();
for(var i = 0; i < floating.length; i++){
alert(floating[i].name());
}