Java LogoThe Simple Definition:

JavaScript is a form of scripting that enables dynamic features to be embedded into web pages to include items that are constantly updated. Examples of usage could be the embedding of an RSS Feed on a website to provide the latest news updates from another website, a dynamic gallery that rotates photos at predetermined periods of time, java script website menus,  or can be used for the display of live feeds such as cams or video feeds from a remote website.

It’s called “client side” scripting as no calls are made on the server that the website is hosted on and where the script is installed. . In web design circles JavaScript is generally found as useful for adding dynamic content to a website but suffers from a unique problem and that is although it is visible to the human eye  the same as the coding , for some reason search engines can’t see it.

If you fill up a whole page with just JavaScript to a search engine bot it is essentially an empty page. Couple this to the fact some people do switch off java in their web browser  Add to that the user has to download Java to add it to their browser and requires updates independently and Java then becomes a bit of an issue!

Finally too much JavaScript does slow down the loading of a web page which can lead to lower rankings with Google and other search engines as they do use page load speed as part of the complex algorithmfor ranking websites. JavaScript does have it’s uses and used in small amounts is a fast way to add dynamic client side content  and interest to a website but used heavily it can be detrimental to a website and its performance.

The Official Definition:

JavaScript is an implementation of the ECMAScript language standard and is typically used to enable programmatic access to computational objects within a host environment. It can be characterized as a prototype-based object-oriented scripting language that is dynamic, weakly typed and has first-class functions. It is also considered a functional programming language like Scheme and OCaml because it has closures and supports higher-order functions.

JavaScript is primarily used in the form of client-side JavaScript, implemented as part of a web browser in order to provide enhanced user interfaces and dynamic websites. However, its use in applications outside web pages—for example in PDF-documents, site-specific browsers and desktop widgets—is also significant.

JavaScript uses syntax influenced by that of C. JavaScript copies many names and naming conventions from Java, but the two languages are otherwise unrelated and have very different semantics. The key design principles within JavaScript are taken from the Self and Scheme programming languages.