JavaScript Statements — JavaScript interactive lesson

Statement Identifiers

JavaScript statements start with a statement identifier to identify the action to be performed.

Statement identifiers are reserved words (cannot be used as variable names or any other things).

Revised July 2025

Statement	Description
{ }	Creates an block of statements
async function	Creates an AsyncFunction object
async function*	Creates an AsyncGeneratorFunction object
await using	Declares local variables that are asynchronously disposed
break	Exits a switch or a loop
class	Declares a class
const	Declares a variable with a constant value
continue	Breaks one iteration (in the loop) if a specified condition occurs, and continues with the next iteration in the loop
debugger	Stops the execution of JavaScript, and calls (if available) the debugging function
do...while	Executes a block of statements and repeats the block while a condition is true
for	Loops through a block of code a number of times
for...in	Loops through the properties of an object
for...of	Loops through the values of an iterable object
for await...of	Loops over async iterable objects
function	Declares a function
function*	Creates a GeneratorFunction object
if...else...else if	Marks a block of statements to be executed depending on a condition
import	Defines a read-only import of a module
import attributes	Defines how a module should be loaded
let	Declares a variable
return	Stops the execution of a function (and returns a value)
switch	Marks a block of statements to be executed depending on different cases
throw	Throws (generates) an error
try...catch...finally	Marks the block of statements to be executed when an error occurs in a try block, and implements error handling
using	Declares local variables that are synchronously disposed
var	Declares a variable
while	Marks a block of statements to be executed while a condition is true

Statement Identifiers

JavaScript statements start with a statement identifier to identify the action to be performed.

Statement identifiers are reserved words (cannot be used as variable names or any other things).

Revised July 2025

Statement	Description
{ }	Creates an block of statements
async function	Creates an AsyncFunction object
async function*	Creates an AsyncGeneratorFunction object
await using	Declares local variables that are asynchronously disposed
break	Exits a switch or a loop
class	Declares a class
const	Declares a variable with a constant value
continue	Breaks one iteration (in the loop) if a specified condition occurs, and continues with the next iteration in the loop
debugger	Stops the execution of JavaScript, and calls (if available) the debugging function
do...while	Executes a block of statements and repeats the block while a condition is true
for	Loops through a block of code a number of times
for...in	Loops through the properties of an object
for...of	Loops through the values of an iterable object
for await...of	Loops over async iterable objects
function	Declares a function
function*	Creates a GeneratorFunction object
if...else...else if	Marks a block of statements to be executed depending on a condition
import	Defines a read-only import of a module
import attributes	Defines how a module should be loaded
let	Declares a variable
return	Stops the execution of a function (and returns a value)
switch	Marks a block of statements to be executed depending on different cases
throw	Throws (generates) an error
try...catch...finally	Marks the block of statements to be executed when an error occurs in a try block, and implements error handling
using	Declares local variables that are synchronously disposed
var	Declares a variable
while	Marks a block of statements to be executed while a condition is true