Download Squad

"Daddy, what's a bookmarklet?" A childish question, perhaps, but not a question a child might ask. The kid might also call them favelets if he was raised on a diet of Internet Explorer. A bookmarklet, or favelet comes from "bookmarks" and "favorites" that you would save in your browser. Bookmarklets are Javascript applications in the form of URLs, and wherever you can store a URL, you can store a bookmarklet. Usually you drag them from the page to your bookmark bar, or you can add them like any favorite or bookmark.

A bookmarklet functions much like a button, but instead of just taking you to a website (like your garden variety bookmark), it does something at that website as well. As I said, it is an application. Some bookmarklets are used to modify a website, even if the effect is an illusion on your machine. Javascript can do some crazy cool things in a browser, and bookmarklets can similarly do some crazy cool things. Unfortunately each browser handles Javascript just a bit differently (and different versions of a browser will behave differently), so your mileage may vary.

Bookmarklets are commonly used to quickly tie into websites that allow you to share information. For example, this handy Delicious bookmarklet that allows you to easily save a URL to your Delicious bookmarks. Normally you'd copy the URL, go to Delicious, then paste it in to the right place and fill out the metadata. With the bookmarklet you simply hit the button (the bookmarklet in your bookmarks bar, or elsewhere in your bookmarks) and it will take whatever site you're on, send you to Delicious, and fill out the URL and title. It usually suggests some tags as well.

Lots of sites provide handy bookmarklets, including VodPod, Tumblr, Reddit and FriendFeed. But here are a few resources you might find handy or fun:

• The Internet Archive has a Wayback bookmarklet so you can see previous versions of a website instamagically (scroll down a bit).
• Prank your friends with the ability to edit any website (well, not Flash sites) using this fun bookmarklet.
• Opera users? Here's a pile of bookmarklets just for you.
• Ever wanted to read some text on a web page in big text, one word at a time? Check out the nifty Spreeder bookmarklet to do just that.
• Finally there's the spiffy Rollyo, which adds a search to any page you visit. Plus, you can save your searches for later.

If you missed it the first time, Lee recently put together a list of 15+ handy bookmarklets.

[Hat tip to Lifehack for another excellent list of bookmarklets]