empty

An empty statement is used to provide no statement, although the JavaScript syntax would expect one.

Sintaxe

;

Descrição

The empty statement is a semicolon (;) indicating that no statement will be executed, even if JavaScript syntax requires one. The opposite behavior, where you want multiple statements, but JavaScript only allows a single one, is possible using a block statement; it combines several statements into a single one.

Exemplos

The empty statement is sometimes used with loop statements. See the following example with an empty loop body:

var arr = [1, 2, 3];

// Assign all array values to 0
for (i = 0; i < arr.length; arr[i++] = 0) /* empty statement */ ;

console.log(arr)
// [0, 0, 0]

Note: It is a good idea to comment the intentional use of the empty statement, as it is not really obvious to distinguish between a normal semicolon. In the following example the usage is probably not intentional:

if (condition);       // Caution, this "if" does nothing!
   killTheUniverse()  // So this gets always executed!!!

Another Example: An if...else statement without curly braces ({}). If three is true, nothing will happen, four does not matter, and also the launchRocket() function in the else case will not be executed.

if (one)
  doOne();
else if (two)
  doTwo();
else if (three)
  ; // nothing here
else if (four)
  doFour();
else
  launchRocket();

Especificações

Browsers compatíveis

Veja também

• Block statement