I want to be able to close an alert box automatically using Javascript after a certain amount of time or on a specific event (i.e. onkeypress). From my research, it doesn't look like that's possible with the built-in alert() function. Is there a way to override it and have control over the dialog box that it opens?
Also, I don't want an override that shows a hidden div as the alert. I need an actual dialog box.
As mentioned previously you really can't do this. You can do a modal dialog inside the window using a UI framework, or you can have a popup window, with a script that auto-closes after a timeout... each has a negative aspect. The modal window inside the browser won't create any notification if the window is minimized, and a programmatic (timer based) popup is likely to be blocked by modern browsers, and popup blockers.