"Unobtrusive JavaScript" is a general approach to the use of JavaScript in web pages. Though the term is not formally defined, its basic principles are generally understood to include:...
In computing, a uniform resource locator or universal resource locator is a specific character string that constitutes a reference to an Internet resource....
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...
. The term is a portmanteau of the terms bookmark and applet, however, an applet is not to be confused with a bookmarklet just as JavaScript
JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
Utility software is system software designed to help analyze, configure, optimize or maintain a computer. A single piece of utility software is usually called a utility or tool....
are stored as bookmarks or hyperlinks, they are designed to add one-click functionality to a browser or web page. When clicked, a bookmarklet performs some function, one of a wide variety such as a search query or data extraction. Usually the applet is a JavaScript
JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
In computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
s for the href attribute of the <a> tag and for bookmarks. The URI scheme
URI scheme
In the field of computer networking, a URI scheme is the top level of the Uniform Resource Identifier naming structure. All URIs and absolute URI references are formed with a scheme name, followed by a colon character , and the remainder of the URI called the scheme-specific part...
, such as http:, file:, or ftp:, specifies the protocol and required form for the rest of the string. Browsers also implement a prefix javascript: that to a parser is just like any other URI. Internally, the browser sees that the protocol is javascript, treats the rest of the string as JavaScript code which is then executed, and uses the resulting string as the new page.
The executing script has access to the current page, which it may inspect and change. If the script returns an undefined type (rather than, say, a string), the browser will not load a new page, with the result that the script simply runs against the current page content. This permits in-place font size and color changes, for example, without a page reload.
An anonymous function can be used to force the script to return an undefined type:
javascript:(function{
/* Statements returning a non-undefined type, e.g. assignments */
});
Usage
Bookmarklets are saved and used as normal bookmarks. As such, they are simple "one-click" tools which add functionality to the browser. For example, they can:
Modify the appearance of a web page within the browser (e.g., change font size, background color, etc.).
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....
, etc.).
Remove redirects from (e.g. Google) search results, to show the actual target url.
Submit the current page to a blogging service such as Posterous, link-shortening service such as su.pr, or bookmarking service such as Delicious.
A web search engine is designed to search for information on the World Wide Web and FTP servers. The search results are generally presented in a list of results often referred to as SERPS, or "search engine results pages". The information may consist of web pages, images, information and other...
, with search term(s) provided by previously selected text, or by a dialog box
Dialog box
In a graphical user interface of computers, a dialog box is a type of window used to enable reciprocal communication or "dialog" between a computer and its user. It may communicate information to the user, prompt the user for a response, or both...
.
Submit the current page to a link validation service, or translation
Translation
Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. Whereas interpreting undoubtedly antedates writing, translation began only after the appearance of written literature; there exist partial translations of the Sumerian Epic of...
service.
Set commonly chosen configuration options when the page itself provides no way to do this.
Installation
"Installation of a bookmarklet" is performed by creating a new bookmark, and pasting the code into the URL destination field. Alternatively, if the bookmarklet is presented as a link, under some browsers it can be dragged and dropped onto the bookmark bar. The bookmarklet can then be run by loading the bookmark normally.
History
Steve Kangas of bookmarklets.com coined the term "bookmarklet", which he started to create based on an idea suggested in the Netscape JavaScript Guide. The term favelet was used early on by Tantek Çelik
Tantek Çelik
Tantek Çelik is a computer scientist of Turkish-American descent and was the Chief Technologist at Technorati. He is one of the principal editors of several CSS Specifications....
on 6 September 2001 (personal email). Brendan Eich
Brendan Eich
Brendan Eich is a computer programmer and creator of the JavaScript scripting language. He is the chief technology officer at the Mozilla Corporation.-Education:...
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....
at Netscape, gave this account of the origin of bookmarklets:
Example
This example bookmarklet performs a Wikipedia search on any highlighted text in the web browser window. In normal use, the following Javascript would be installed to a bookmark in a browser bookmarks toolbar. From then on, after selecting any text, clicking the bookmarklet performs the search.
External links
Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or...
, 1 June 2009. Retrieved 18 July 2009
The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.
