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Comma operator

var iNum = 10;

iNum += 10;

Compound assignment operators exist for each of the major mathematical operations and a few others

as well:

Multiply/Assign (

)

Divide/Assign (

)

Modulus/Assign (

)

Add/Assign (

)

Subtract/Assign (

)

Left Shift/Assign (

<<=

)

Signed Right Shift/Assign (

>>=

)

Unsigned Right Shift/Assign (

>>>=

)

Comma operator

The comma operator allows execution of more than one operation in a single statement. Example:

var iNum1=1, iNum2=2, iNum3=3;

Most often, the comma operator is used in the declaration of variables.

Statements

ECMA-262 describes several

statements

for ECMAScript. Essentially, statements define most of the syn-

tax of ECMAScript and, typically, use one or more keywords to accomplish a given task. Statements can

be simple, such as telling a function to exit, or complicated, such as specifying a number of commands to

be executed repeatedly. This section introduces all the standard ECMAScript statements.

The if statement

One of the most frequently used statements in ECMAScript (and indeed, in many languages), is the

statement. The

statement has the following syntax:

if (

condition

)

statement1

else

statement2

The condition can be any expression; it doesn’t even have to evaluate to an actual Boolean value.

ECMAScript converts it to a Boolean for you. If the condition evaluates to

true

, statement1 is executed;

if the condition evaluates to

false

, statement2 is executed. Each of the statements can be either a single

line or a code block (a group of code lines enclosed within braces). For example:

ECMAScript Basics

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