What's the best way to make external images and JS files to not affect page load time?

Question

On a lot of the pages I work with there are a lot of external(non-critical) external images and js files that get called that affect the load time. One of these is a tracking pixel for an ad company that sometimes can take a few seconds to load and you can see this hanging in the browser so it gives a poor user experience. Is there a way that I can load these and not have them count as the initial page load? I've seen similar things that launch a timer and once the timer fires they load but I'm worried that if the user leaves the page too quickly the tracking pixel wont have time to load.

Answer 1

Not really - the point of tracking using a gif is to track users regardless of whether they have javascript or not. Delaying the load of the gif would require javascript, so would defeat the point and potentially mess up your stats.

The best method is to put these 'unnecessary for page load' things at the end of the code, inside the closing body tag.

Answer 2

If you can load the tracking pixel further down on the webpage, preferably as close to the end BODY tag as possible, it will likely process all other content prior to that image first, making the page load appear to occur faster in the event the image isn't loading very fast.

This can be explained (if taken slightly out of context) by Yahoo YSlow's "Best Practices for Speeding up your Website" section on put scripts at the bottom.