componentFromPoint 简单实例

最新推荐文章于 2021-02-13 01:42:59 发布

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本文介绍如何通过JavaScript函数componentFromPoint定位鼠标指针下的HTML元素，包括滚动条、大小调整手柄等常见组件的位置。

Syntax

sScrollComponent = object.componentFromPoint(iCoordX, iCoordY)

Parameters

iCoordX Required. Integer that specifies the client window coordinate of x.
iCoordY Required. Integer that specifies the client window coordinate of y.

Return Value

empty string	Component is inside the client area of the object.
outside	Component is outside the bounds of the object.
scrollbarDown	Down scroll arrow is at the specified location.
scrollbarHThumb	Horizontal scroll thumb or box is at the specified location.
scrollbarLeft	Left scroll arrow is at the specified location.
scrollbarPageDown	Page-down scroll bar shaft is at the specified location.
scrollbarPageLeft	Page-left scroll bar shaft is at the specified location.
scrollbarPageRight	Page-right scroll bar shaft is at the specified location.
scrollbarPageUp	Page-up scroll bar shaft is at the specified location.
scrollbarRight	Right scroll arrow is at the specified location.
scrollbarUp	Up scroll arrow is at the specified location.
scrollbarVThumb	Vertical scroll thumb or box is at the specified location.
handleBottom	Bottom sizing handle is at the specified location.
handleBottomLeft	Lower-left sizing handle is at the specified location.
handleBottomRight	Lower-right sizing handle is at the specified location.
handleLeft	Left sizing handle is at the specified location.
handleRight	Right sizing handle is at the specified location.
handleTop	Top sizing handle is at the specified location.
handleTopLeft	Upper-left sizing handle is at the specified location.
handleTopRight	Upper-right sizing handle is at the specified location.

<HTML>
<HEAD>
<SCRIPT>
/*When this function is activated, an alert pops up displays the component at the position of the pointer. */

function ComponentSnapShot(){
	var sElem = "";
	sElem = document.body.componentFromPoint(event.clientX,event.clientY);

	if (sElem=="")
	alert("No component there!");
	else
	alert("Component: " + sElem);
}
</SCRIPT>



</HEAD>
<!-- There are several different events that can be used with componentFromPoint. Below are a few of them.
Be carefull! Not all mouse events can be used with componentFromPoint.  -->
<BODY  onmousedown="ComponentSnapShot()" oncontextmenu="ComponentSnapShot()">

<TEXTAREA COLS=500 ROWS=500>
This text forces scroll bars to appear in the window.
</TEXTAREA>
</BODY>
</HTML>

iCoordX	Required. Integer that specifies the client window coordinate of x.
iCoordY	Required. Integer that specifies the client window coordinate of y.