Recently I discovered that Firefox lets you override alert and confirm window object methods. I tried this with prototype and surprisingly it just worked! (Note that it is not tested in IE or Opera and others yet, but it also works in Safari). <div id="test" style="background:red;color:white;display:none;"></div> <script type="text/javascript"> window.confirm = function (s) { alert(s); }; window.alert = function (s) [...]