Javascript [Electronic resources] : The Definitive Guide (4th Edition) نسخه متنی

Availability

JavaScript 1.0

Synopsis

<input type="type"onfocus="handler">
input.onfocus

Description

The onfocus property of an Input object specifies
an event handler function that is invoked when the user transfers
keyboard focus to that input element.
Calling focus( ) to set focus to an element does
not invoke onfocus for that object.

The initial value of this property is a function that contains the
semicolon-separated JavaScript statements specified by the
onfocus attribute of the HTML tag that defined the
object. When an event handler function is defined by an HTML
attribute, it is executed in the scope of
element rather than in the scope of the
containing window.

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.

The onfocus event handler is available for all
form elements except the Hidden element. In Netscape on Unix
platforms, however, it is invoked only for the text-entry elements:
Text, Textarea, Password, and FileUpload. Note that in JavaScript
1.1, the Window object also defines an onfocus
event handler.

See Also

Window.onfocus; Chapter 19; Event, EventListener,
and EventTarget in the DOM reference section