Javascript
Overview:
2 sessions
Subjects:
- JS in webpages
- JS data types & variables
- loops
- control structure
- functions
What is JavaScript?
JavaScript is a scripting or programming language that allows you to implement complex things on web pages — every time a web page does more than just sit there and display static information for you to look at — displaying timely content updates, interactive maps, animated 2D/3D graphics, scrolling video jukeboxes, etc. — you can bet that JavaScript is probably involved.[1]
Variables
https://codepen.io/PublicationStation/pen/wmpRyX
A variable is a container for some value. Like a number to be used in a sum, or a text string.
Most importantly: variables' values can change. They aren't the values themselves, but containers for values, like little boxes that you can store things in.
https://mdn.mozillademos.org/files/13506/boxes.png
[2]
In order to use variables, we need to:
- declare the variables
- values can be attached to them
Code pen example: https://codepen.io/PublicationStation/pen/ZxvwpW
Data types
Code pen exampled: https://codepen.io/PublicationStation/pen/wmjXLR
JS features a few data types, or in other words different types of content, which can be used as values of a variable. These include:
- strings: pieces of text, always wrapped in single or double quotation marks
var name = "I am Pluto"; - numbers (both integers and float point numbers)
var discovered = 1930; - booleans: true or false values (outside quotation mais)
var planet = false; var dwarf=true; - Arrays (or lists): a container of multiple values enclosed in square brackets and separated by commas
var planets=["Pluto", "Neptune", "Uranus", "Saturn"]- the values of arrays can be accessed by their location within the array var
p=planets[0]; var s=planets[3]
- the values of arrays can be accessed by their location within the array var
- Object: is a list of items, each item, stored by a name-value pair. The values can be strings, numbers, lists or even other objects.
var saturn = {"moons": ["Pan", "Daphnis", " Atlas", "Prometheus", "Pandora"], "Volume":"95.159 Earths"}
Exercise
https://codepen.io/PublicationStation/pen/QmVRdp?editors=1011
References
- ↑ "What is JavaScript?" MDN Web Docs, 28 Mar. 2018, https://developer.mozilla.org/en-US/docs/Learn/JavaScript/First_steps/What_is_JavaScript.
- ↑ "Storing the information you need — Variables." MDN Web Docs, 28 Mar. 2018, developer.mozilla.org/en-US/docs/Learn/JavaScript/First_steps/Variables.
