简单的放大缩小，显示坐标功能。
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演示代码：
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> Document </TITLE>
<style type="text/css">
body{
padding : 0px ;
margin : 0px;
background-color : #999999 ;
}
.DivMain {
position : absolute ;
text-align : center ;
overflow : hidden ;
}
.DivMenu {
position : absolute ;
text-align : left ;
overflow : hidden ;
}
.ImgMain {
position : absolute ;
overflow : hidden ;
border : 0px ;
}
.TBMain {
background-color : #CCCCCC ;
padding : 0px ;
border : 0px ;
z-index : 99 ;
line-height : 18px ;
}
.TBMenu {
background-color : #FFCCCC ;
padding : 0px ;
border : 0px ;
z-index : 99 ;
color: #000000 ;
}
.HrScroll {
margin : 0px;
background-color : #FFFFFF ;
padding : 0px ;
border : 0px ;
z-index : 99 ;
color : #000000 ;
border-spacing : 0px;
width : 160px ;
height : 10px ;
}
</style>
<SCRIPT LANGUAGE="JavaScript">
<!--
var originalWidth ;
var originalHeight ;
var objDivMain ;
var objTbMain ;
var objImg ;
var ObjDrag ;
var objDivMenu ;
var objTbMemu ;
var objbtnImgInfo ;
var objDivFlag;
var objHrScroll;
var oRcts ;
var oTextRange ;
function setInit(obj) {
objDivMain = document.getElementById("divMain") ;
objTbMain = document.getElementById("TbMain") ;
objDivMenu = document.getElementById("DivMenu") ;
objTbMenu = document.getElementById("TbMenu") ;
objImg = document.getElementById("imgMain") ;
objbtnImgInfo = document.getElementById("btnImgInfo") ;
objDivFlag = document.getElementById("DivFlag");
objHrScroll = document.getElementById("HrScroll");
originalWidth = obj.width;
originalHeight = obj.height;
objImg.style.width = originalWidth;
objImg.style.height = originalHeight;
fmImgZoom.FitScreen.click();
}
function setFitScreen() {
initImg(objImg);
}
function setOriginal() {
var intBodyWidth ;
var intBodyHeight ;
intBodyWidth = document.body.clientWidth ;
intBodyHeight = document.body.clientHeight ;
objImg.style.left = 0 ;
objImg.style.top = 0 ;
objImg.style.width = originalWidth;
objImg.style.height = originalHeight;
objImg.style.zoom = 1 ;
objDivMain.style.width = intBodyWidth ;
objDivMain.style.height = intBodyHeight - objTbMain.clientHeight;
fnWritePos(objImg.style.left,objImg.style.top,objImg.style.zoom);
}
function initImg(objCurrent) {
var intBodyWidth ;
var intBodyHeight ;
intBodyWidth = document.body.clientWidth ;
intBodyHeight = document.body.clientHeight ;
objTbMain.style.top = 0;
objTbMain.style.height = 20;
objTbMain.style.width = intBodyWidth;
objDivMain.style.left = 0 ;
objDivMain.style.height = intBodyHeight - objTbMain.clientHeight;
objDivMain.style.width = intBodyWidth ;
initZoom(objCurrent);
}
function initZoom(obj){
var intObjWidth ;
var intObjHeight ;
var intDivHeight ;
var intZoomRatio ;
intDivHeight = objDivMain.style.pixelHeight;
intObjHeight = obj.style.pixelHeight;
intZoomRatio = intDivHeight / intObjHeight;
obj.style.zoom = intZoomRatio ;
obj.style.top = 0;
obj.style.left = 0;
fnWritePos (obj.style.left,obj.style.top,obj.style.zoom) ;
}
function fnMouseDown(obj) {
ObjDrag=obj;
ObjDrag.setCapture();
ObjDrag.l=event.x-ObjDrag.style.pixelLeft;
ObjDrag.t=event.y-ObjDrag.style.pixelTop;
}
function fnMouseMove() {
if(ObjDrag!=null) {
ObjDrag.style.left = event.x-ObjDrag.l;
ObjDrag.style.top = event.y-ObjDrag.t;
fnWritePos(ObjDrag.style.left,ObjDrag.style.top,ObjDrag.style.zoom);
}
}
function fnMouseUp() {
if(ObjDrag!=null) {
ObjDrag.releaseCapture();
ObjDrag=null;
}
}
function fnZoomIn() {
objImg.style.zoom = parseFloat(objImg.style.zoom) + 0.01 ;
fnWritePos(objImg.style.left,objImg.style.top,objImg.style.zoom);
}
function fnZoomOut() {
if(objImg.style.zoom>0.01){
objImg.style.zoom = parseFloat(objImg.style.zoom) - 0.01 ;
fnWritePos(objImg.style.left,objImg.style.top,objImg.style.zoom);
}
}
function fnDivMouseDown() {
if ( event.button == 2 && event.srcElement.id != "imgMain") {
objDivMenu.style.top = event.y;
objDivMenu.style.left = event.x;
objDivMenu.style.visibility = "";
oTextRange = objHrScroll.createTextRange() ;
oRcts = oTextRange.getClientRects();
oBndRct = objDivFlag.getBoundingClientRect();
objDivFlag.style.top = oRcts[0].top;
objDivFlag.style.left = oRcts[0].left + parseInt(objImg.style.zoom * 10) ;
objDivFlag.style.visibility = "";
}
if ( event.button == 1 && event.srcElement.id != "imgMain") {
objDivMenu.style.visibility = "hidden";
objDivFlag.style.visibility = "hidden";
}
}
function fnWritePos(intLeft,intTop,intZoom) {
objbtnImgInfo.innerText = " ImgLeft:" + intLeft + " ImgTop:" + intTop + " ImgZoom:" + intZoom ;
}
function fnSlipMouseDown(obj) {
ObjDrag=obj;
ObjDrag.setCapture();
ObjDrag.l = event.x - ObjDrag.style.pixelLeft;
ObjDrag.t = ObjDrag.style.pixelTop;
}
function fnSlipMouseMove() {
if(ObjDrag!=null) {
if(event.x >= oRcts[0].left && event.x <= oRcts[0].right ){
ObjDrag.style.left = event.x - objDivFlag.offsetWidth / 2;
}
ObjDrag.t = ObjDrag.style.pixelTop;
var intCurrentPos = ObjDrag.style.pixelLeft - oRcts[0].left + objDivFlag.offsetWidth / 2;
var intPicZoom = intCurrentPos / 10;
objImg.style.zoom = intPicZoom;
fnWritePos(objImg.style.left,objImg.style.top,objImg.style.zoom);
}
}
function fnSlipMouseUp() {
if(ObjDrag!=null) {
ObjDrag.releaseCapture();
ObjDrag=null;
}
}
function setDisplay() {
if(objImg.style.visibility == ""){
objImg.style.visibility = "hidden";
}
else{
objImg.style.visibility = "";
}
}
function fnContextMenu() {
window.event.returnValue=false;
}
//-->
</SCRIPT>
</HEAD>
<BODY oncontextmenu="fnContextMenu()">
<form name="fmImgZoom">
<TABLE id="tbMain" class="TBMain">
<TR>
<TD>
<input type="button" name="ZoomIn" value="ZoomIn" onclick="fnZoomIn()">
<input type="button" name="ZoomOut" value="ZoomOut" onclick="fnZoomOut()">
<input type="button" name="Original" value="Original" onclick="setOriginal()">
<input type="button" name="FitScreen" value="FitScreen" onclick="setFitScreen()">
<input type="button" name="btnView" value="hide/view" onclick="setDisplay()">
<input id="btnImgInfo" size="50">
</TD>
</TR>
</TABLE>
<div id="divMain" class="DivMain" onmousedown="fnDivMouseDown()"><img src="" id="imgMain" class="imgMain" onload="setInit(this)" onmousedown="fnMouseDown(this)" onmousemove="fnMouseMove()" onmouseup="fnMouseUp()" ></div>
<div id="divMenu" class="DivMenu" style="visibility:hidden">
<TABLE class="TBMenu">
<TR>
<TD>10%</TD>
<TD><button id="HrScroll" class="HrScroll"><hr noshade></button> </TD>
<TD>1600%</TD>
</TR>
</TABLE>
</div>
<DIV ID="DivFlag" STYLE="position:absolute;visibility:hidden;width:1px;height:10px;z-index:99" onmousedown="fnSlipMouseDown(this)" onmousemove="fnSlipMouseMove()" onmouseup="fnSlipMouseUp()" onmouseover="this.style.cursor ='hand'" onmouseout="this.style.cursor=''">↑</DIV>
</form>
</BODY>
</HTML>