Name
Window.onfocus — the handler invoked when a window is given focus
Availability
JavaScript 1.1
Synopsis
<body onfocus="handler" ... > <frameset onfocus="handler" ... >window.onfocus
Description
The onfocus property of a Window specifies an
event handler function that is invoked when the window is given
keyboard focus.
The initial value of this property is a function that contains the
semicolon-separated JavaScript statements specified by the
onfocus attribute of
the <body> or
<frameset> tags.
In the Netscape 4 event model, the onfocus handler
function is passed an Event object as an argument. In the IE event
model, no argument is passed, but the applicable Event object is
available as the event property of the Window
object that contains the element.
Usage
If your web page has animation, you can use the
onfocus event handler to start the animation and
the onblur handler to stop it, so it runs only
when the user is paying attention to the window.
See Also
Window.blur( ), Window.focus( ), Window.onblur; Chapter 19; Event, EventListener, and EventTarget in the DOM reference section
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