javascript notes go here
Javascript
It is an integrated programming language.
A browser uses an interpreter or a scripting engine to translate your instructions to the page.
Its process is:
- browser receives an html page
- creates a model of the page and stores it in memory
- shows the page using the engine
The saying, calling a method of an object refers to OBJECT.METHOD()
Basics of JS
A script is a series of instructions that a coputer can follow one-by-one. Each individual instruction or step is konown as a statement. Statements should end with semicolons!
| Single-line comments | Multi-line comments |
|---|---|
use //TEXT |
use /* TEXT */ |
A variable, in my words, similar to mathematics definition it is a placeholder for a number, name, data type, etc. As in math, you must always introduce (declare) the variable before assigning (=) it a value aka var X;.
A few data types are:
- Numeric: for numbers, can be any rational number
- String: for text and other characters (always in matching quotes)
- Boolean: true or false
*You can always change the value of your variable simply by declaring it a new value.
Rules for naming variables:
- must begin with a letter, dollar sign, or underscore, NOT a number
- DO NOT use dash or period
- cannot use keywords specific to code like “var” and reserved words
- Though it IS case-sensitive, it is not good practice to give files the same name
- feel free to use camel case or snake case
Live notes from class
new Date() gets the current date.
today.getHours() gets todays hours.
document.write(<h3> VAR or TEXT </h3>) spits out the text or string stored in the variable.