Comma Operator (,)

Comma Operator (,) (JavaScript)


Causes two expressions to be executed sequentially.

expression1, expression2


Any expression.


Any expression.

The , operator causes the expressions to be executed in left-to-right order. A common use for the , operator is in the increment expression of a for loop. For example:

for (i = 0; i < 10; i++, j++)
   k = i + j;

The for statement allows only a single expression to be executed at the end of every pass through a loop. The , operator allows multiple expressions to be treated as a single expression, so both variables can be incremented.


Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information.

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