这是一个可以用鼠标随意拖动图标的小程序

这是一个可以用鼠标随意拖动图标的小程序

- 中国WEB开发者网络 (http://www.webasp.net)
-- 网页特效 (http://www.webasp.net/javascript/)
--- 这是一个可以用鼠标随意拖动图标的小程序 (http://www.webasp.net/javascript/1/378.htm)

-- 发布日期： 2005-06-06

<BODY onLoad="init()">




<style type="text/css">

#plane1 {position:absolute; left:290; top:170; width:121; z-index:0}

#plane2 {position:absolute; left:400; top:250; width:118; z-index:0}

</style>
<script language="JavaScript">

//Modified by the CoffeeCup HTML Editor++

// Global variables for platform branching

var isNav, isIE

if (parseInt(navigator.appVersion) >= 4) {

if (navigator.appName == "Netscape") {

isNav = true

} else {

isIE = true

}

}

// ***Begin CSS custom API Functions***

// Set zIndex property

function setZIndex(obj, zOrder) {

obj.zIndex = zOrder

}

// Position an object at a specific pixel coordinate

function shiftTo(obj, x, y) {

if (isNav) {

obj.moveTo(x,y)

} else {

obj.pixelLeft = x

obj.pixelTop = y

}

}

// ***End API Functions***

// Global holds reference to selected element

var selectedObj

// Globals hold location of click relative to element

var offsetX, offsetY

// Find out which element has been clicked on

function setSelectedElem(evt) {

if (isNav) {

// declare local var for use in upcoming loop

var testObj

// make copies of event coords for use in upcoming loop

var clickX = evt.pageX

var clickY = evt.pageY

// loop through all layers (starting with frontmost layer)

// to find if the event coordinates are in the layer

for (var i = document.layers.length - 1; i >= 0; i--) {

testObj = document.layers[i]

if ((clickX > testObj.left) &&

(clickX < testObj.left + testObj.clip.width) &&

(clickY > testObj.top) &&

(clickY < testObj.top + testObj.clip.height)) {

// if so, then set the global to the layer, bring it

// forward, and get outa here

selectedObj = testObj

setZIndex(selectedObj, 100)

return

}

}

} else {

// use IE event model to get the targeted element

var imgObj = window.event.srcElement

// make sure it's one of our planes

if (imgObj.parentElement.id.indexOf("plane") != -1) {

// then set the global to the style property of the element,

// bring it forward, and say adios

selectedObj = imgObj.parentElement.style

setZIndex(selectedObj,100)

return

}

}

// the user probably clicked on the background

selectedObj = null

return

}

// Drag an element

function dragIt(evt) {

// operate only if a plane is selected

if (selectedObj) {

if (isNav) {

shiftTo(selectedObj, (evt.pageX - offsetX), (evt.pageY - offsetY))

} else {

shiftTo(selectedObj, (window.event.clientX - offsetX), (window.event.clientY - offsetY))

// prevent further system response to dragging in IE

return false

}

}

}

// Set globals to connect with selected element

function engage(evt) {

setSelectedElem(evt)

if (selectedObj) {

// set globals that remember where the click is in relation to the

// top left corner of the element so we can keep the element-to-cursor

// relationship constant throughout the drag

if (isNav) {

offsetX = evt.pageX - selectedObj.left

offsetY = evt.pageY - selectedObj.top

} else {

offsetX = window.event.offsetX

offsetY = window.event.offsetY

}

}

// block mouseDown event from forcing Mac to display

// contextual menu.

return false

}

// Restore elements and globals to initial values

function release(evt) {

if (selectedObj) {

setZIndex(selectedObj, 0)

selectedObj = null

}

}

// Turn on event capture for Navigator

function setNavEventCapture() {

if (isNav) {

document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP)

}

}

// Assign event handlers used by both Navigator and IE (called by onLoad)

function init() {

if (isNav) {

setNavEventCapture()

}

// assign functions to each of the events (works for both Navigator and IE)

document.onmousedown = engage

document.onmousemove = dragIt

document.onmouseup = release

}

</script>
<div id=plane1><img name="planePic1" src="http://www.webasp.net/images/logo.gif" border=0 style="cursor:move"></div>
<div id=plane2><img name="planePic1" src="http://www.webasp.net/images/logo.gif" border=0 style="cursor:move"></div>

webasp.net