The void operator is used to evaluate an expression without returning a value.
This operator returns undefined and is commonly used in place of the onClick event handler.
The following example uses the void Operator to Call a Function.
<html> <head> <title>Examples of the void Operator</title> <script language="JavaScript"> <!-- function myFunc(){ alert("You clicked the link!"); } --> </script> </head> <body> <A HREF="javascript:void(myFunc())">Click here to call the function</A> </body> </html>