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

Availability

JavaScript 1.0

Synopsis

<a ... onmouseover="handler" ... >
<area ... onmouseover="handler" ...
> link.onmouseover

Description

The onmouseover property of a Link object
specifies an event handler function that is invoked when the user
moves the mouse over a hypertext link. The initial value of this
property is a function that contains the JavaScript statements
specified by the onmouseover attribute of the
<a> or <area> tag
that defined the Link object. When an event handler function is
defined in this way by an HTML attribute, it is executed in the scope
of element rather than in the scope of the
containing window.

By default, the browser displays the URL that a hypertext link refers
to in the status line whenever the mouse goes over the link. The
onmouseover event handler is invoked before the
URL is displayed. If the handler returns true, the
browser does not display the URL. Thus, an event handler function
that returns true can display a custom message in
the status line by setting the Window.status
property to any desired value.

Note that while this event handler returns true to
tell the browser not to perform its default action (displaying the
URL of a link), the onclick event handler of the
Link object must return false to tell the browser
not to take its default action (following the link). This
incompatibility exists for historical reasons. The standard for Form
and form element event handlers is to return false
to prevent the browser from performing a default action.

In the Netscape 4 event model, the onmouseover
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 hypertext link.

See Also

Chapter 19; EventListener, EventTarget, and
MouseEvent in the DOM reference section