javascript 任意用鼠标拖动图片
脚本说明:
第一步:把如下代码加入<body>区域中
<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++
//http://www.coffeecup.com
// 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 planePic1" SRC="http://www.jojoo.net/logo.gif" BORDER=0></DIV>
<DIV planePic1" SRC="http://www.jojoo.net/logo.gif" BORDER=0></DIV>
第二步:把<body>区域中内容改为:
<body bgcolor="#fef4d9" onLoad="init()">
