Updated September 25, 2010Doc Sheldon
A friend in the Dojo pointed something out today that came as a bit of a surprise to me. It probably shouldn’t have, as it has obviously been around quite a while. But in case I’m not the only one around here that missed, it, I’m sharing it here. Many of you are probably already aware of it, but then, many of you are younger than I am, and perhaps even a bit more alert (although I’m pretty sharp, after my nap).
So hush up and respect your elders!
Firefox is set by default to do a great many things. A few of them are readily altered via your menu bar. Others are not so easily changed. Or for that matter, even visible.
One such is the prefetch instruction. This is an instruction embedded in a link, which tells the browser to go ahead and start preloading the target of the link, in anticipation of a need to load it for viewing by the user. Preloading a large file or image can accelerate pageload, hence improving the user experience.
Those embedded instructions are placed on a page by the developer or webmaster, in this format:
<link rel="prefetch" href="/images/big.jpeg">
Now, I’m all for improving the user experience. In fact, I see that as my responsibility numero uno. I don’t even have a problem with it being a default setting in Firefox, provided we’re made aware of it. Firefox already has the tendency to open a large number of connections, unbeknownst to the user, and those connections not only slow down our browsing, they can also present a security risk.
And I also understand a webmaster wanting to use rel=”prefetch” to keep his bounce rate down. However, as consumers, I think we each have a right to know and control what our system is doing.
I also don’t think my browser should be downloading cookies from websites that I haven’t even visited.
So, if you’re not already on top of this, and you’d like to disable the Firefox prefetch function (this works in Flock, too, by the way), here’s the procedure:
- In the Firefox Address Bar type about:config and press Enter.
- You’ll be confronted with a screen warning that you may void your warranty by continuing. Assuming you decide to continue…
- Find the option that is named network.prefetch-next and double-click on it.
- Change the value to false.
- Now, the rel=”prefetch” instruction will not be heeded, when encountered.
See? That wasn’t so bad. You spent more time scrolling down to the network lines, than anything else. 😉 After you’ve restarted your browser, you can check your Task Manager and I’m sure you’ll see the improvement.
This should free up a considerable block of resources for you, depending on the nature of your online activities. I estimate it freed up 20-25% for me, but then, I often have ten or twelve tabs open. And personally, I haven’t noted any appreciable increase in loadtime.