In JavaScript, the void
keyword is an operator that takes an expression and evaluates it, but then always returns undefined
. It is often used in event handlers for hyperlinks and buttons to prevent the default behavior of navigating to a new page or submitting a form.
Here is an example of using the void
operator in an HTML hyperlink:
<a href="javascript:void(0);" onclick="myFunction()">Click me</a>
In this example, the href
attribute of the hyperlink is set to "javascript:void(0);"
, which means that clicking the link will not cause the browser to navigate to a new page. Instead, the onclick
event is triggered, which calls the myFunction()
function.
The void
operator is used in this case to ensure that the hyperlink does not perform any default action when clicked. The expression passed to void
is simply 0
, which is evaluated but then discarded because void
always returns undefined
.
The void
operator can also be used to create self-executing anonymous functions, like this:
void function() {
// do something here
}();
In this example, the void
operator is used to suppress the return value of the anonymous function, which is executed immediately. This technique is sometimes used to create a block of code that is executed once, without creating any variables or functions in the global scope.