Today I wanted to add a quick spinner to a web page making an AJAX call to the server. Generally I prefer to make code fast enough so that spinner should be obsolete but sometimes turn-around can take longer than one second so I gave up and added one. I decided on nice small GIF spinner which should be in-lined where button/link is. But running locally from Eclipse it just froze until AJAX call returned which is so irritating. Even though I remove spinner as soon as call returns (i.e. before browser starts to render the DOM) but still, no go.
And after deploy on the server Voilà! Everything works perfectly. Makes one wonder how DOM manipulation is done when emulating JS running in hosted mode? As long as one kills (hides) spinner before any intensive processing on client side it works like a charm.