Question

If I have something like

alert = 0;

in another script.

This is in another script is and my code cannot load before that script.

How can I call the original alert method in my script?

Answer 1

Before overriding the original alert, save it.

var origAlert = alert;
alert = 0;
origAlert("foo");

Demo: http://jsfiddle.net/jfriend00/tnNE7/

---

If you can’t save the original value, the only other way I know of to get access to it is in an iframe. Here’s an example:

alert = 0;
var iframe = document.createElement("iframe");
iframe.height = 0;
iframe.width = 0;
document.body.appendChild(iframe);
iframe.contentWindow.alert.call(window, "foo");​

Working example: http://jsfiddle.net/jfriend00/waMEV/

I haven’t tried this in all browsers, but it works in Chrome, IE and Firefox and I think it should work in other browsers.