Day 33 - 7/10

Plan: Wait for confirmation from Ms Ly then move to javascript

Progress:

Output:

• document.getElementById("demo") / document.getElementsByClassName("name")

• both ' ' and " " are accepted

• document.getElementById("demo").innerHTML = ; : to write into an html element

• document.write(5 + 6); : to write into html output; if used after html document is loaded will replace every existing html (example: onclick= "document.write(5 + 6)" ) (note: used only in testing)

• alert(5+6); : alert box to display data

• console.log(5+6); : for debugging

• window.print() : to open print window

Statements:

• white spaces are ignored

• max-line width should be 80 characters; best line-break point is after an operator

Syntax (or rules)

• fixed value called Literals; variable value called Variables

• identifier (or variable names) : start with letter, dollar sign ($) or an underscore ( _ ), not number; uppercase and lowercase are sensitive

• hyphens ( - ) are not allowed

Variables

• declare variables before use

• let and const are more used; let for changable variables; const for constant variables; var for old browsers

• re-declare a variable will not make it lose its value; re-declare doesnt work with let or const

• after a number in quotes, the rest of the numbers will be treated as string and no whitespace

• ( $ ) not common, often used as an alias for the main function

• ( _ ) not common, often used as an alias for "private (hidden)" variables

Let

• in a { } block, variable declared with var can be accessed from outside, the rest cannot

Const

• cannot redeclared; reassigned; have block scope

• a variable declared inside and outside the block is not the same

• Redeclaring an existing var or let variable to const, in the same scope, is not allowed

• Reassigning an existing const variable, in the same scope, is not allowed