void is an important keyword in JavaScript which can be used as a unary operator that appears before its single operand, which may be of any type. This operator specifies an exdivssion to be evaluated without returning a value.
Syntax
The syntax of void can be either of the following two −
The most common use of this operator is in a client-side javascript: URL, where it allows you to evaluate an exdivssion for its side-effects without the browser displaying the value of the evaluated exdivssion.
Here the exdivssion alert ('Warning!!!') is evaluated but it is not loaded back into the current document −
See this example:
Output:
Click the following, This won't react at all...
Click me!Take a look at the following example. The following link does nothing because the exdivssion "0" has no effect in JavaScript. Here the exdivssion "0" is evaluated, but it is not loaded back into the current document.
See this example:
Output:
Click the following, This won't react at all...
Click me!Another use of void is to purposely generate the undefined value as follows.
Output:
Click the following to see the result:
