onmousewheel Event

Fires when the wheel button is rotated.

dhtml语法

Inline HTML <ELEMENT onmousewheel = "handler" ... > All platforms
Event property object.onmousewheel = handler JScript only
object.onmousewheel = GetRef("handler") Visual Basic Scripting Edition (VBScript) 5.0 or later only
Named script <SCRIPT FOR = object EVENT = onmousewheel> Internet Explorer only

Event Information

Bubbles Yes
Cancels Yes
To invoke Rotate the wheel button.
Default action Scrolls the page up or down.

Event Object Properties

Although event handlers in the DHTML Object Model do not receive parameters directly, a handler can query an event object for data.
available properties
altKey Sets or retrieves a value that indicates the state of the ALT key.
altLeft Sets or retrieves a value that indicates the state of the left ALT key.
cancelBubble Sets or retrieves whether the current event should bubble up the hierarchy of event handlers.
clientX Sets or retrieves the x-coordinate of the mouse pointer's position relative to the client area of the window, excluding window decorations and scroll bars.
clientY Sets or retrieves the y-coordinate of the mouse pointer's position relative to the client area of the window, excluding window decorations and scroll bars.
ctrlKey Sets or retrieves the state of the CTRL key.
ctrlLeft Sets or retrieves the state of the left CTRL key.
offsetX Sets or retrieves the x-coordinate of the mouse pointer's position relative to the object firing the event.
offsetY Sets or retrieves the y-coordinate of the mouse pointer's position relative to the object firing the event.
screenX Retrieves the x-coordinate of the mouse pointer's position relative to the user's screen.
screenY Sets or retrieves the y-coordinate of the mouse pointer's position relative to the user's screen.
shiftKey Sets or retrieves the state of the SHIFT key.
shiftLeft Retrieves the state of the left SHIFT key.
srcElement Sets or retrieves the object that fired the event.
type Sets or retrieves the event name from the event object.
wheelDelta Sets or retrieves the distance and direction the wheel button has rolled.
x Sets or retrieves the x-coordinate, in pixels, of the mouse pointer's position relative to a relatively positioned parent element.
y Sets or retrieves the y-coordinate, in pixels, of the mouse pointer's position relative to a relatively positioned parent element.

Remarks

The onmousewheel event is the only event that exposes the wheelDelta property. This property indicates the distance that the wheel button has rotated, expressed in multiples of 120. A positive value indicates that the wheel button has rotated away from the user. A negative value indicates that the wheel button has rotated toward the user. See the example below.

DHTML代码范例

The following example shows how to use the onmousewheel event and the wheelDelta parameter to expand and contract a picture in response to the wheel button being moved.
<HTML>
<HEAD>
<SCRIPT>
var count = 10;
function Picture()
{
count = Counting(count);
Resize(count);
return false;
}
function Counting(count){
if (event.wheelDelta >= 120)
count++;
else if (event.wheelDelta <= -120)
count--;
return count;
}
function Resize(count){
oImage.style.zoom = count + '0%';
}
</SCRIPT>
</HEAD>
<BODY>
<img id="oImage" src="Sample.jpg" onmousewheel="Picture()" width="283"
height="212" >
</BODY>
</HTML>
This feature requires Microsoft® Internet Explorer 6 or later. Click the following icon to install the latest version. Then reload this page to view the sample.

applies to

A, ADDRESS, APPLET, AREA, B, BDO, BIG, BLOCKQUOTE, BODY, BUTTON, CAPTION, CENTER, CITE, CODE, CUSTOM, DD, DFN, DIR, DIV, DL, document, DT, EM, EMBED, FIELDSET, FONT, FORM, hn, HR, I, IMG, INPUT type=button, INPUT type=checkbox, INPUT type=file, INPUT type=image, INPUT type=reset, INPUT type=password, INPUT type=radio, INPUT type=submit, INPUT type=text, KBD, LABEL, LEGEND, LI, LISTING, MAP, MARQUEE, MENU, nextID, NOBR, OL, P, PLAINTEXT, PRE, RT, RUBY, S, SAMP, SELECT, SMALL, SPAN, STRIKE, STRONG, SUB, SUP, TABLE, TBODY, TD, TEXTAREA, TFOOT, TH, THEAD, TR, TT, U, UL, VAR, XMP

更多语法参考

onscroll, onmousemove, onmousedown, onmouseout, onmouseover, onmouseup