Riferimento JavaScript
Questa sezione riguardante JavaScript contiene informazioni riguardo a tale linguaggio. Leggi altre informazioni riguardo a questa documentazione (en-US).
Oggetti globali
Questo capitolo documenta tutti gli oggetti standard predefiniti di JavaScript, con i loro metodi e le loro proprietà.
{{page('/it/docs/Web/JavaScript/Reference/Global_Objects', 'Oggetti_standard_(per_categoria)')}}
Statements
Questo capitolo documenta tutti gli statements e le dichiarazioni JavaScript.
For an alphabetical listing see the sidebar on the left.
Control flow
Block
(en-US)- A block statement is used to group zero or more statements. The block is delimited by a pair of curly brackets.
break
- Terminates the current loop, switch, or label statement and transfers program control to the statement following the terminated statement.
continue
(en-US)- Terminates execution of the statements in the current iteration of the current or labeled loop, and continues execution of the loop with the next iteration.
Empty
- An empty statement is used to provide no statement, although the JavaScript syntax would expect one.
if...else
(en-US)- Executes a statement if a specified condition is true. If the condition is false, another statement can be executed.
switch
- Evaluates an expression, matching the expression's value to a case clause, and executes statements associated with that case.
throw
- Throws a user-defined exception.
try...catch
(en-US)- Marks a block of statements to try, and specifies a response, should an exception be thrown.
Declarations
var
- Declares a variable, optionally initializing it to a value.
-
let
- Declares a block scope local variable, optionally initializing it to a value.
-
const
(en-US) - Declares a read-only named constant.
Functions and classes
function
(en-US)- Declares a function with the specified parameters.
-
function*
- Generators functions enable writing iterators more easily.
return
(en-US)- Specifies the value to be returned by a function.
-
class
(en-US) - Declares a class.
Iterations
do...while
(en-US)- Creates a loop that executes a specified statement until the test condition evaluates to false. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.
for
(en-US)- Creates a loop that consists of three optional expressions, enclosed in parentheses and separated by semicolons, followed by a statement executed in the loop.
-
for each...in
- Iterates a specified variable over all values of object's properties. For each distinct property, a specified statement is executed.
for...in
(en-US)- Iterates over the enumerable properties of an object, in arbitrary order. For each distinct property, statements can be executed.
-
for...of
- Iterates over iterable objects (including arrays, array-like objects, iterators and generators), invoking a custom iteration hook with statements to be executed for the value of each distinct property.
while
(en-US)- Creates a loop that executes a specified statement as long as the test condition evaluates to true. The condition is evaluated before executing the statement.
Others
debugger
(en-US)- Invokes any available debugging functionality. If no debugging functionality is available, this statement has no effect.
-
export
- Used to export functions to make them available for imports in external modules, another scripts.
-
import
- Used to import functions exported from an external module, another script.
label
(en-US)- Provides a statement with an identifier that you can refer to using a
break
orcontinue
statement.
-
with
(en-US) - Extends the scope chain for a statement.
Espressioni e operatori
Questo capitolo documenta espresisioni e operatori di JavaScript.
{{page('/it/docs/Web/JavaScript/Reference/Operators', "Expressions_and_operators_by_category", "", 1)}}
Funzioni
Questo capitolo documenta come usare le funzioni in JavaScript.