HTML 元素的 ondragenter 事件
| ondragenter Event |
DHTML文档教程 |
Fires on the target element when the user drags the object to a valid drop target.
dhtml语法
| Inline HTML |
<ELEMENT ondragenter = "handler" ... > |
All platforms |
| Event property |
object.ondragenter = handler |
JScript only |
| object.ondragenter = GetRef("handler") |
Visual Basic Scripting Edition (VBScript) 5.0 or later only |
|
| Named script |
<SCRIPT FOR = object EVENT = ondragenter> |
Internet Explorer only |
Event Information
| Bubbles |
Yes |
| Cancels |
Yes |
| To invoke |
· Drag the selection over a valid drop target within the browser. · Drag the selection to a valid drop target within another browser window. |
| Default action |
Calls the associated event handler. |
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.
Remarks
You can handle the ondragenter event on the source or on the target object. Of the target events, it is the first to fire during a drag operation. Target events use the getData method to stipulate which data and data formats to retrieve. The list of drag-and-drop target events includes:
· onbeforepaste
· onpaste
· ondragenter
· ondragover
· ondragleave
· ondrop
when scripting custom functionality, use the returnvalue property to disable the default action.
DHTML代码范例
This example shows when and where each event fires during a drag-and-drop operation by listing each event and the name of the object firing it in a list box.
<HEAD>
<SCRIPT>
var oNewOption;
// Code for dynamically adding options to a select.
function ShowResults()
{ // Information about the events
// and what object fired them.
arg = event.type + " fired by " + event.srcElement.id;
oNewOption = new Option();
oNewOption.text = arg;
oResults.add(oNewOption,0);
}
</SCRIPT>
</HEAD>
<BODY>
<P>Source events are wired up to this text box.</P>
<INPUT ID=txtDragOrigin VALUE="Text to Drag"
ondragstart="ShowResults()"
ondrag="ShowResults()"
ondragend="ShowResults()"
>
<P>Target events are bound to this text box.</P>
<INPUT ID=txtDragDestination VALUE="Drag Destination"
ondragenter="ShowResults()"
ondragover="ShowResults()"
ondragleave="ShowResults()"
ondrop="ShowResults()"
>
<SELECT ID=oResults SIZE=30>
<OPTION>List of Events Fired
</SELECT>
</BODY>