What is a Bookmarklet?

Bookmarklet is a combination of the names and meanings of the two words “bookmark” and “applet.” In essence it is a small application, typically only a few lines of JavaScript code, which allow the user to perform a specific function. It is stored as a bookmarked URL in the user’s web browser. When it is activated by being clicked on, a bookmarklet performs a basic task like a search engine query or making a change to the appearance or configuration of a web page.

Basically, a bookmarklet is nothing more than a URL that starts with “javascript:” rather than the standard URL tag “http://”. Because of this change of the tag, the browser understands that Javascript is the protocol to be used and it treats all of the strings of code that follow using Javascript code. When executed, the code will have access to the current page and will be free to carry out whatever it was designed to do. Notice that bookmarklets do not work on web pages using the https: protocol.

Bookmarklets change elements of a web page as well as change settings such as font color without having to reload the web page. Essentially, it allows the user to play with the elements of the current instance of the page and its appearance in a safer manner that does not change the source code of the site.

Bookmarklets are typically stored in your browser’s toolbar. Once you have navigated to a particular web page, you can click on your bookmarklet in order to perform such tasks like getting rid of the crufty sidebars of a web page and enlarge the text to make it easier to read, or for detecting the original language of the text of a web page and translating it into your own language.