小方框中浏览大图

<style type="text/css">
<!--
#pic {
 width:480px;
 height:320px;
 border: 3px solid #ccc;
 background-image: url(images/butong_net.jpg);
 background-repeat: no-repeat;
 background-position: 0px 0px;
 cursor: move;
}
-->
</style>
<script type="text/javascript">
<!--
var p = new Array();
var speed = 0.05;  //速度
var picWidth = 1280;  // 大图的宽高
var picHeight = 971;
var x,y // 鼠标点下去时背景的坐标
var x_new,y_new  //位移
var haveclick = false;

function getmouseposition(event)
{
 if(document.all)
 {
  x = document.body.scrollLeft+event.clientX;
  y = document.body.scrollTop+event.clientY;
 }else
 {
  x = event.layerX;
  y = event.layerY;
 } 
 haveclick = true;
}
function movestop()
{
 haveclick = false;
}

function movestart(event)
{
if(haveclick)
{
 if(document.getElementById('pic').style.backgroundPosition.length==0)
  {document.getElementById('pic').style.backgroundPosition="0px 0px";}
 p = document.getElementById('pic').style.backgroundPosition.split(" ")

 if(document.all)
 { 
  x_new = document.body.scrollLeft+event.clientX;
  y_new = document.body.scrollTop+event.clientY;
 }else
 { 
  x_new = event.layerX;
  y_new = event.layerY; 
 }
 
 x2 = (speed*(x_new-x)+parseInt(p[0])).toString(10);    // 计算位移量
 y2 = (speed*(y_new-y)+parseInt(p[1])).toString(10);
 
 if (x2<-picWidth+420) x2=-picWidth+420;
 if (y2>0) y2=0;
 if (x2>0) x2=0;
 if (y2<-picHeight+300) y2=-picHeight+300;

 document.getElementById('pic').style.backgroundPosition=x2+"px "+y2+"px";
}
}
-->
</script>

 

<div id="pic" onmousedown="getmouseposition(event)" onmousemove="movestart(event)" onmouseup="movestop()" onmouseout="movestop()"> </div>