Javascript Window Shake

This evening I came accross the window.moveBy() JavaScript function and thought it would be cool to shake the browser window when a user fails to log in. It turns out that I was not the only one thinking this, but none of the examples worked for me. Some had no proper delays, others only worked from the page header, and some were plain unreadable.

I’m no Javascript guru, but I hacked this together which is working pretty nicely. It is in fact almost undistinguishable from the Apple login window shake at a login failure:

<script type="text/javascript">
if (window.moveBy) {
	delay = 70;
	shakes = 3;
	window.moveBy(-10, 0);
	for (j = shakes; j > 0; j--) {
		setTimeout( "window.moveBy(20, 0)", j*delay );
		setTimeout( "window.moveBy(-20, 0)",
					j*delay+(delay/2));
	}
	setTimeout( "window.moveBy(10, 0)", (shakes+1)*delay );
}
</script>

In my case, I surrounded this code with a Tapestry @Conditional and made it into a reusable Tapestry component so that I can make any window shake as soon as it contains an error.

The code will work anywhere on your page, but I advise you to put it at the bottom of the HTML. This will make sure that the content is shown in the browser before you shake it.

It’s visually much stronger than just adding an errortext to the page. If people log in a couple of times a day, they don’t even notice extra text on the screen. This will “shake” them awake

Have fun!

LED’s in your livingroom?

In some countries, there is some talk on banishing the classic (incandescant) lightbulb. I think this whole discussion is needless. The only reason why it exists, is that the fluorescent bulbs are often of mediocre quality, and certain people are here to enforce their bad tastes upon us “for a greater purpose”.

Don’t get me wrong, I really like trees and birds around my house, and I would be more than happy to install energy-efficient appliances in my home, even if they cost me slightly more. But especially if I’m paying more, I expect to get a certain level of quality.

Because of the inefficiency of incandescent bulbs, and the number of bulbs in my household, I decided to look around for energy efficient solutions. Particulary LED lighting caught my interest, because it is not only energy efficient, it’s also dimmable with normal (cheap) floor dimmers. They even stay cold enough so that children touching them do not burn their fingers.