How to show a spinner while an iframe is loading

Hi,

     Does anyone know how we can show a spinner while an IFrame is getting loaded. After providing src value to frame element ex:

var newItem = aras.IomInnovator.newItem("", "");
var newItemId = aras.generateNewGUID();
newItem.setID(newItemId);

aras.uiOpenEmptyWindowEx(newItem.node);
var newWindowName = aras.mainWindowName + "_" + newItemId;
var newWindow = aras.windowsByName[newWindowName];

newWindow.frameElement.src = "./example/index.html"; 

Then It takes time to load the iframe...... During which the spinner should be visible.

Thanks,

Sourav