最近忙着做JS，在JS里头有用到鼠标的一些事件时，通常我都是把鼠标事件包含在一个JS文件中调用
<script type="text/javascript" src="js/sb_cd.js"></script>

在鼠标事件中若包含如下鼠标的特效，就会导致事件触发：js/sb_cd.js
// JavaScript Document 

var sb_cd_a_Colour='fff000';
var sb_cd_b_Colour='00ff00';
var sb_cd_c_Colour='ff00ff';
var sb_cd_Size=120;

var sb_cd_YDummy=new Array(),sb_cd_XDummy=new Array(),sb_cd_xpos=0,sb_cd_ypos=0,sb_cd_ThisStep=0;sb_cd_step=0.6;
if (document.layers){
window.captureEvents(Event.MOUSEMOVE);
function sb_cd_nsMouse(evnt){
sb_cd_xpos = window.pageYOffset+evnt.pageX+6;
sb_cd_ypos = window.pageYOffset+evnt.pageY+16;
}
window.onMouseMove = sb_cd_nsMouse;
}
else if (document.all)
{
function sb_cd_ieMouse(){
sb_cd_xpos = document.body.scrollLeft+event.x+6;
sb_cd_ypos = document.body.scrollTop+event.y+16;
}
document.onmousemove = sb_cd_ieMouse;
}

function sb_cd_swirl(){
for (i = 0; i < 3; i++)
 {
 sb_cd_YDummy[i]=sb_cd_ypos+sb_cd_Size*Math.sin((1*Math.sin((sb_cd_ThisStep)/10))+i*2)*Math.sin((sb_cd_ThisStep)/4);
 sb_cd_XDummy[i]=sb_cd_xpos+sb_cd_Size*Math.cos((1*Math.sin((sb_cd_ThisStep)/10))+i*2)*Math.sin((sb_cd_ThisStep)/4);
 }
sb_cd_ThisStep+=sb_cd_step;
setTimeout('sb_cd_swirl()',10);
}

var sb_cd_amount=10;
if (document.layers){
for (i = 0; i < sb_cd_amount; i++)
{
document.write('<layer name=sb_cd_nsa'+i+' top=0 left=0 width='+i/2+' height='+i/2+' bgcolor='+sb_cd_a_Colour+'></layer>');
document.write('<layer name=sb_cd_nsb'+i+' top=0 left=0 width='+i/2+' height='+i/2+' bgcolor='+sb_cd_b_Colour+'></layer>');
document.write('<layer name=sb_cd_nsc'+i+' top=0 left=0 width='+i/2+' height='+i/2+' bgcolor='+sb_cd_c_Colour+'></layer>');
}
}
else if (document.all){
document.write('<div id="sb_cd_ODiv" style="position:absolute;top:0px;left:0px">'
+'<div id="sb_cd_IDiv" style="position:relative">');
for (i = 0; i < sb_cd_amount; i++)
{
document.write('<div id=sb_cd_x style="position:absolute;top:0px;left:0px;width:'+i/2+';height:'+i/2+';background:'+sb_cd_a_Colour+';font-size:'+i/2+'"></div>');
document.write('<div id=sb_cd_y style="position:absolute;top:0px;left:0px;width:'+i/2+';height:'+i/2+';background:'+sb_cd_b_Colour+';font-size:'+i/2+'"></div>');
document.write('<div id=sb_cd_z style="position:absolute;top:0px;left:0px;width:'+i/2+';height:'+i/2+';background:'+sb_cd_c_Colour+';font-size:'+i/2+'"></div>');
}
document.write('</div></div>');
}
function sb_cd_prepos(){
var sb_cd_ntscp=document.layers;
var sb_cd_msie=document.all;
if (document.layers){
for (i = 0; i < sb_cd_amount; i++)
{
 if (i < sb_cd_amount-1)
 {
 sb_cd_ntscp['sb_cd_nsa'+i].top=sb_cd_ntscp['sb_cd_nsa'+(i+1)].top;sb_cd_ntscp['sb_cd_nsa'+i].left=sb_cd_ntscp['sb_cd_nsa'+(i+1)].left;
 sb_cd_ntscp['sb_cd_nsb'+i].top=sb_cd_ntscp['sb_cd_nsb'+(i+1)].top;sb_cd_ntscp['sb_cd_nsb'+i].left=sb_cd_ntscp['sb_cd_nsb'+(i+1)].left;
 sb_cd_ntscp['sb_cd_nsc'+i].top=sb_cd_ntscp['sb_cd_nsc'+(i+1)].top;sb_cd_ntscp['sb_cd_nsc'+i].left=sb_cd_ntscp['sb_cd_nsc'+(i+1)].left;
 }
else 
 {
 sb_cd_ntscp['sb_cd_nsa'+i].top=sb_cd_YDummy[0];sb_cd_ntscp['sb_cd_nsa'+i].left=sb_cd_XDummy[0];
 sb_cd_ntscp['sb_cd_nsb'+i].top=sb_cd_YDummy[1];sb_cd_ntscp['sb_cd_nsb'+i].left=sb_cd_XDummy[1];
 sb_cd_ntscp['sb_cd_nsc'+i].top=sb_cd_YDummy[2];sb_cd_ntscp['sb_cd_nsc'+i].left=sb_cd_XDummy[2];
 }
}
}
else if (document.all){
for (i = 0; i <  sb_cd_amount; i++)
{
 if (i < sb_cd_amount-1)
 {
 sb_cd_msie.sb_cd_x[i].style.top=sb_cd_msie.sb_cd_x[i+1].style.top;sb_cd_msie.sb_cd_x[i].style.left=sb_cd_msie.sb_cd_x[i+1].style.left;
 sb_cd_msie.sb_cd_y[i].style.top=sb_cd_msie.sb_cd_y[i+1].style.top;sb_cd_msie.sb_cd_y[i].style.left=sb_cd_msie.sb_cd_y[i+1].style.left;
 sb_cd_msie.sb_cd_z[i].style.top=sb_cd_msie.sb_cd_z[i+1].style.top;sb_cd_msie.sb_cd_z[i].style.left=sb_cd_msie.sb_cd_z[i+1].style.left;
 }
else
 {
 sb_cd_msie.sb_cd_x[i].style.top=sb_cd_YDummy[0];sb_cd_msie.sb_cd_x[i].style.left=sb_cd_XDummy[0];
 sb_cd_msie.sb_cd_y[i].style.top=sb_cd_YDummy[1];sb_cd_msie.sb_cd_y[i].style.left=sb_cd_XDummy[1];
 sb_cd_msie.sb_cd_z[i].style.top=sb_cd_YDummy[2];sb_cd_msie.sb_cd_z[i].style.left=sb_cd_XDummy[2];
 }
}
}
setTimeout("sb_cd_prepos()",10);
}
function sb_cd_Start(){
sb_cd_swirl(),sb_cd_prepos()
}
window.onload=sb_cd_Start;

其中页面的代码如下：
当打开DW时，通常会先有这样预先定义好的代码，先看看第一行
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>

<body>
<script type="text/javascript" src="js/sb_cd.js"></script>
</body>
</html>

问题找了很久，都不知道是什么地方的问题。后来才发现是DW生成的代码第一句
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
使得这个鼠标事件不运行。，原来这里声明了后面的鼠标事件必须遵循这个DTD文档 的规则。
而不事件中的一些定义没有遵循，所以这个鼠标事件即不触发，也不报错。

官方是这样定义 DOCTYPE HTML PUBLIC 的