About Bookmarklets

...answers to basic questions

How do they work?
  Each bookmarklet is a tiny program (a JavaScript application) contained in a bookmark (the URL is a "javascript:" URL) which can be saved and used the same way you use normal bookmarks. The idea was suggested in the Netscape JavaScript Guide.

JavaScript has been used by page authors on millions of webpages; Bookmarklets allow anybody to use JavaScript - on whatever page you choose (not just your own page).

Why are they free?
  There is a limited amount of room in a bookmark URL field; this means that each bookmarklet is much simpler than a traditional program - usually they are only two or three lines of code.
  I don't feel that it would be appropriate to charge money for such small programs, even if they are extremely useful. It is better to give them away in the hope that others will make more of them. Because bookmarklets are a relatively new concept, I do ask for restraint on the part of redistributors; you can share some of these with your friends but please let me get some feedback before you redistribute large numbers of them on the web!

Are they safe?
  Bookmarklets are safer than traditional software for the following reasons:
1.  They are extremely simple. With only a few lines of code it's hard to make a programming error that isn't detected immediately.
2.  You don't install software. Traditional software programs can produce conflicts with other programs on your hard drive. Bookmarklets work entirely within your web browser, so they can't independently interfere with the functioning of other programs.
3. Because you don't install software, you don't have the security risks of traditional software (which can install files all over your hard drive). Your hard drive is protected by JavaScript security restrictions.
4. Even if something goes wrong (say, you try to use a Netscape-only bookmarklet on Internet Explorer) the worst thing that is likely to happen is that you will get a JavaScript error message. Furthermore, this site has been designed (through server-side scripting) to make it impossible for you to get a bookmarklet that doesn't work on your browser.

Are they the coolest thing since sliced bread?
  Um, maybe. Sliced bread is pretty cool. Some people think that for something to be cool it has to be big and complex; bookmarklets are tiny and simple. I am especially proud of the concept of the "user-defined hyperlink" (under the "Search Tools") - these allow documents to be a "two-way street", as opposed to the traditional one-way street of author-determined presentational flow. You be the judge!


Steve Kangas
"Chief of Rocket Science"

You may find the answers to other questions in the Bookmarklet Help section, or by reading the Ideas behind Bookmarklets.

  See the