[查看演示]  源码如下
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<STYLE>.drag {
CURSOR: hand; POSITION: relative
}
</STYLE>
<script>
var sPosition;
var showPerc=100;
document.onmousedown=dragLayer
document.onmouseup=new Function("dragMe=false")

var Color= new Array();
Color[0] = "00";
Color[1] = "11";
Color[2] = "22";
Color[3] = "33";
Color[4] = "44";
Color[5] = "55";
Color[6] = "66";
Color[7] = "77";
Color[8] = "88";
Color[9] = "99";
Color[10] = "AA";
Color[11] = "BB";
Color[12] = "CC";
Color[13] = "DD";
Color[14] = "EE";
Color[15] = "FF";

var rVal,gVal,bVal, cCol
function chgBg() {
cCol = document.bgColor; rVal=cCol.substr(1,2); gVal=cCol.substr(3,2); bVal=cCol.substr(5,2);
ind = Math.round(showPerc/16); if (ind < 0) ind = 0; if (ind > 15) ind=15;

if (kObj.id =="knobImg") document.bgColor="#"+Color[ind]+gVal+bVal;
if (kObj.id =="knobImg1") document.bgColor="#"+rVal+Color[ind]+bVal;
if (kObj.id =="knobImg2") document.bgColor="#"+rVal+gVal+Color[ind];
}

var dragMe=false, kObj, yPos,direction
function moveLayer() {
if (event.button==1 && dragMe) {
oldY = kObj.style.pixelTop; kObj.style.pixelTop=temp2+event.clientY-yPos;
if (kObj.style.pixelTop > oldY) direction="dn"; else direction="up";
if (kObj.style.pixelTop < 2 && direction=="up") {kObj.style.pixelTop=2; direction="dn";}
if (kObj.style.pixelTop > 102 && direction=="dn") {kObj.style.pixelTop=102; direction="up";}
sPosition=kObj.style.pixelTop; showPerc = (perCent[0].checked) ? sPosition-2 : (sPosition-2)/2*5;
chgBg();
return false; }
}
function dragLayer() {
if (!document.all) return;
if (event.srcElement.className=="drag") {dragMe=true; kObj=event.srcElement; temp2=kObj.style.pixelTop; yPos=event.clientY; document.onmousemove=moveLayer; }
}
</SCRIPT>
现在本例子只简单的改变了背景的颜色，也可以将这使用方法应用<br>
到如聊天室等程序上，可以让你的应用增添色彩. </div>
<p></P>
<DIV id=outerLyr
style="BACKGROUND-COLOR: #000000; HEIGHT: 120px; LEFT: 233px; POSITION: absolute; TOP: 111px; WIDTH: 23px; Z-INDEX: 1"><IMG
class=drag id=knobImg src="../wybj/images/knob.jpg"
style="HEIGHT: 17px; LEFT: 2px; TOP: 100px; WIDTH: 20px; Z-INDEX: 3">

<DIV id=innerLyr
style="BACKGROUND-COLOR: #777777; HEIGHT: 117px; LEFT: 2px; POSITION: absolute; TOP: 2px; WIDTH: 20px; Z-INDEX: 2">
<DIV id=barLyr
style="BACKGROUND-COLOR: #000000; HEIGHT: 110px; LEFT: 9px; POSITION: absolute; TOP: 5px; WIDTH: 2px; Z-INDEX: 1"></DIV></DIV></DIV>
<DIV id=outerLyr1
style="BACKGROUND-COLOR: #000000; HEIGHT: 120px; LEFT: 268px; POSITION: absolute; TOP: 111px; WIDTH: 23px; Z-INDEX: 1"><IMG
class=drag id=knobImg1 src="../wybj/images/knob.jpg"
style="HEIGHT: 17px; LEFT: 2px; TOP: 100px; WIDTH: 20px; Z-INDEX: 3">

<DIV id=innerLyr1
style="BACKGROUND-COLOR: #777777; HEIGHT: 117px; LEFT: 2px; POSITION: absolute; TOP: 2px; WIDTH: 20px; Z-INDEX: 2">
<DIV id=barLyr1
style="BACKGROUND-COLOR: #000000; HEIGHT: 110px; LEFT: 9px; POSITION: absolute; TOP: 5px; WIDTH: 2px; Z-INDEX: 1"></DIV></DIV></DIV>
<DIV id=outerLyr2
style="BACKGROUND-COLOR: #000000; HEIGHT: 120px; LEFT: 300px; POSITION: absolute; TOP: 111px; WIDTH: 23px; Z-INDEX: 1"><IMG
class=drag id=knobImg2 src="../wybj/images/knob.jpg"
style="HEIGHT: 17px; LEFT: 2px; TOP: 100px; WIDTH: 20px; Z-INDEX: 3">

<DIV id=innerLyr2
style="BACKGROUND-COLOR: #777777; HEIGHT: 117px; LEFT: 2px; POSITION: absolute; TOP: 2px; WIDTH: 20px; Z-INDEX: 2">
<DIV id=barLyr2
style="BACKGROUND-COLOR: #000000; HEIGHT: 110px; LEFT: 9px; POSITION: absolute; TOP: 5px; WIDTH: 2px; Z-INDEX: 1"></DIV></DIV></DIV>
<P><INPUT name=perCent type=radio value=false> Prozent <INPUT
CHECKED name=perCent type=radio value=true> 255 </P>

<div style="position: absolute; top: 10; right: 10; width: 148; height: 18;cursor:hand">
<input type="button" name="Button" value="查看源代码" onClick= 'window.location = "view-source:" + window.location.href'></div>