P3: Describe
the purpose and function of JavaScript and jQuery
Introduction
JavaScript is a scripting language that is normally used in
the development of HTML and CSS websites. JavaScript contains many features of a programming
languages but it is not a programming language because it doesn’t possess key
attributes that most programming language possess. JavaScript is a client side and not server side. For this reason, this
document is going to be set within the parameters of describing the purpose of JavaScript
and its key features that makes it similar to programming language and
exploring features that also makes it dissimilar to a programming language. The
functions of JavaScript and JQuery as a development tool is also going to be
explored in this document.
JavaScript
JavaScript can be described as a scripting language that is
used for the sole purpose of making web pages interactive. JavaScript is an
interpreted language for this reason, it runs on the client computer and you do
not need an extended program in order to run it on your computer. (Tech, 2015) JavaScript is executed by web browsers and it is mainly used for interactivity and validation. JavaScript can
change HTML content in the development of a site and one of the methods that it
uses is through ‘getElementById()’. As well as changing HTML it can also change
CSS styles. It is one of the primary ways that web developers use to validate
data on webpages. For example, JavaScript is very likely to have been RUN when
you don’t fill out mandatory text fields on an online form and an error message
pops up. JavaScript is normally used by developers on occasion where they need
the code to run after the page has loaded as JavaScript is a language that is
supported by all browsers used by clients. Most interactive features of
webpages such as slideshows are normally done by website developers using JavaScript.
The reason why JavaScript is very popular is because of its functions that
allows it to fit with the dynamic web era that we are currently in. This means
that JavaScript is suitable for most sites nowadays that changes and adaption
is a key aspect of the functionality of the site. For example, JavaScript is
used to recognise if clients are visting the site on their phone or on a
computer and then decides whether or not to change the way that the content
renders to either a mobile platform version or computer version. (Wilde, 2013)
JavaScript features similar and dissimilar to programming language
Features of JavaScript that makes it similar and dissimilar to
a programming language is going to be explained in the table below:
JavaScript features similar to programming language
|
JavaScript features dissimilar to programming
language
|
Features such as the use of variables, conditional statement and
event handlers is attributes that are normally affiliated with programming
languages. This is a feature of JavaScript that makes it similar to
programming languages such as Perl or C. Variables are containers for values
which are norm in programming languages also conditional statements which
allow different codes to run at the same time. Conditional statement is what
allowed me to create validation if text boxes are not completed on a form
before submission.
|
Features that make JavaScript dissimilar to programming languages is
the fact that the variables that is declared with JavaScript are always made
public, its features does not allow it to privatise variables as you can do
with most programming languages.
|
Another feature that JavaScript has in common with programming
language is that it has datatype (arrays).
|
Another major reason why JavaScript is dissimilar to programming
languages is because features that are non-existent such as algebraic data
types and pattern matching that are also available with other standard
programming language.
|
Another reason why JavaScript is similar to a functional programing
language is because functions are first class objects, there are closures and
higher order of functions.
|
JQuery
On the other hand, JQuery is simply a library where
pre-coded JavaScript are stored as open-source for developers that want to use
them. JQuery is a library of JavaScript that is very popular due to the fact
that it is easy to use and powerful. The main purpose of JQuery is so web
developers can easily apply common JavaScripts to their websites during
implementation without consuming time. JQuery functions are important as a
development tool for website developers because it allows to apply JavaScript
to their work without having to deal with debugging common errors. Also with JavaScript
code in JQuery they are normally effective and short which helps with the implementation
process of the JavaScript. (Wilde, 2013) Overall, JQuery is a
development tool that most advanced website developers use due to the fewer
lines code. For example, the following evidences using JQuery or JavaScript to
change the background colour of a body tag: - As you can see it will be quicker
to use JQuery rather than JavaScript.
jQuery
$ (‘body’)
.css (‘background’, ‘#ccc’);
JavaScript
Function
changeBachground(color) {
Document.body.style.background = color;
}
Onload=”changeBackground
(‘red’);”
Bibliography
Johann, 2014. stack. [Online]
Available at: http://stackoverflow.com/questions/3962604/is-JavaScript-a-functional-programming-language
[Accessed 18 04 2016].
Available at: http://stackoverflow.com/questions/3962604/is-JavaScript-a-functional-programming-language
[Accessed 18 04 2016].
Tech, 2015. abouttech.
[Online]
Available at: http://JavaScript.about.com/od/reference/p/JavaScript.htm
[Accessed 18 04 2016].
Available at: http://JavaScript.about.com/od/reference/p/JavaScript.htm
[Accessed 18 04 2016].
Wilde, B.,
2013. Udemy. [Online]
Available at: https://blog.udemy.com/jquery-vs-JavaScript/
[Accessed 18 04 2016].
Available at: https://blog.udemy.com/jquery-vs-JavaScript/
[Accessed 18 04 2016].
