Javascript Basic From W3C

Front 1

How do you prevent browsers which don't support javascript from displaying javascript as page content

Back 1

Add an html comment tag, <!--, before the first javascript statement and a comment closing tag, --> after the last javascript statement

Front 2

Where do you put the javascript in a page if you do not want the script to be executed immediately

Back 2

Put the javascript inside of a function which should be placed in the head of the page to keep it separate from page content

Front 3

How do you refer an html document to an external javascript file

Back 3

Point to the .js file in teh "src" attribute of the <script> tag. <script type="text.javascript" srcr="xxx.js"></script>

Front 4

Javascript statement tells browser to write something

Back 4

document.write("Hello!");

Front 5

What is a javascript block

Back 5

A block makes the sequence of javascript statements executed together and starts with a left curly bracket, {, and ends with a right curly bracket, }

Front 6

How do your write comments on one line

Back 6

Use //

Front 7

How do you write multi line comments

Back 7

Use /* before and */ after sooo
/*
This is an
awesome comment
*/

Front 8

What are the rules for naming javascript variables

Back 8

they are case sensitive and must begin with a letter or underscore character

Front 9

How do you declare variables in javascript

Back 9

with the var statement
examples:
var x;
var carname;

Front 10

How do you assign values to variables?

Back 10

var x=5;
var carname="Volvo";
Text values require quotes while numbers do not

Front 11

List the js arithmetic operators

Back 11

+ addition, - subtraction, * multiplication, / division, % modulus, ++ increment, -- decrement

Front 12

List the js assignment operators

Back 12

=, +=, -=, *=, /=, %=

Front 13

List the js comparison operators

Back 13

== is equal to, === is exactly equal to (value and type), != is not equal, > greather, < less, >= greater than or equal to, <= less than or equal to

Front 14

List the js logical operators

Back 14

&& and, || Or, ! not