Window alert()

Display an alert box:

alert("Hello! I am an alert box!!");

More examples below.

Description

The alert() method displays an alert box with a message and an OK button.

The alert() method is used when you want information to come through to the user.

The alert box takes the focus away from the current window, and forces the user to read the message.

Do not overuse this method. It prevents the user from accessing other parts of the page until the alert box is closed.

alert(message)

Parameter	Description
message	Optional. The text to display in the alert box.

NONE

Alert box with line-breaks:

alert("Hello\nHow are you?");

Alert the hostname of the current URL:

alert(location.hostname);

alert() is supported in all browsers:


Chrome	Edge	Firefox	Safari	Opera	IE
Yes	Yes	Yes	Yes	Yes	Yes