Javascript Basics

Front 1

JavaScript Objects

Back 1

Array
Boolean
Date
Math
Number
String
RegExp

Front 2

Browser Objects

Back 2

Window
Navigator
Screen
History
Location

Front 3

Major DOM Objects

Back 3

Document
Events
Elements

Front 4

Ways to Create an Array

Back 4

1.
var myCars=new Array(); // regular array (add an optional integer
myCars[0]="Saab"; // argument to control array's size)
myCars[1]="Volvo";
myCars[2]="BMW";

2.
var myCars=new Array("Saab","Volvo","BMW"); // condensed array

3.
var myCars=["Saab","Volvo","BMW"]; // literal array

Front 5

Is "var" optional?

myObj = 1;

same as ?

var myObj = 1;

Back 5

They mean different things. If you use var the variable is declared within the scope you are in (e.g. of the function). If you don't use var, the variable is automatically global, and attached to the global object (window, if you are doing it in the browser).

Front 6

If...else if...else Statement

Back 6

if (condition1)
{
code to be executed if condition1 is true
}
else if (condition2)
{
code to be executed if condition2 is true
}
else
{
code to be executed if condition1 and condition2 are not true
}

Front 7

Switch Statement

Back 7

switch(n)
{
case 1:
execute code block 1
break;
case 2:
execute code block 2
break;
default:
code to be executed if n is different from case 1 and 2
}

Front 8

How to Define a Function

Back 8

function functionname(var1,var2,...,varX)
{
some code
}

Front 9

The for Loop

Back 9

for (var=startvalue;var<=endvalue;var=var+increment)
{
code to be executed
}

Front 10

The while Loop

Back 10

while (var<=endvalue)
{
code to be executed
}

Front 11

The break Statement

Back 11

var i=0;
for (i=0;i<=10;i++)
{
if (i==3)
{
break;
}
document.write("The number is " + i);
document.write("<br />");
}

Front 12

For...In Statement

Back 12

for (variable in object)
{
code to be executed
}

Front 13

The try...catch Statement

Back 13

try
{
//Run some code here
}
catch(err)
{
//Handle errors here
}

Front 14

The Throw Statement

Back 14

throw(exception)

The exception can be a string, integer, Boolean or an object.

Front 15

Insert Special Characters

Back 15

var txt="We are the so-called \"Vikings\" from the north.";