Function in Javascript

Function are subprograms which are used to compute a value or perform a task.

Type of Function

– Library or Built-in functions Ex: – valueOf( ) , write( ), alert( ) etc

– User-defined functions

Example

Rules

  • Function name only starts with a letter, an underscore ( _ ).
  • Function name cannot start with a number.
  • Do not use reserved keywords. e.g. else, if etc.
  • Function names are case-sensitive in JavaScript.

How Function Call Works

The code inside a function isn‟t executed until that function is called.

Rajesh Kumar
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