JQuery animate () with browser performance and page load time

The way jQuery animate () works is that it uses a timer that periodically fires and invokes a function that updates the DOM to reflect the state of the animation. Typically animations are relatively short and they may cover a fair amount of screen real estate, so I suspect (without confirming) that the timer expires, and is reset, at a fairly high rate to generate a smooth animation. Since your animation takes a long time, you might be able to modify the animate function so that the rate at which the animation proceeds can be set via an option. In your case you’d only need to update every 250ms or so since you’re covering about 3-4 pixels per second, roughly.