在一个JS的学习资料上，看到一个关于黑客帝国文字下落的特效！挺好玩的，贴个源码分享一下！
<HTML>
<HEAD>
<TITLE>《黑客帝国》中的字符下落效果</TITLE>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
</HEAD>
<style type="text/css">
body
{
overflow:hidden;
margin:0;
background-color:#000000;
font-family:宋体;
}
DIV.#heike
{
overflow:hidden;
position:relative;
top:5%;
90%;
height:90%;
border-style:solid;
border-1;
border-color:#009900;
}
</style>
<script language="javascript">
var strCount;
var str;
var Color;
var Font;
var sLine = "0<br/>1<br/>0<br/>1<br/>0<br/>0<br/>1<br/>0<br/>1<br/>0<br/>";
function OnLoad()
{
strCount = 40;
str = [];
Color = [];
Font = [];
Color[0] = "#002211"; //文字的颜色
Color[1] = "#003311";
Color[2] = "#005511";
Color[3] = "#008811";
Color[4] = "#00BB99";
Color[5] = "#114411";
Color[6] = "#335566";
Color[7] = "#668899";
Color[8] = "#99BBAA";
Color[9] = "#CECECC";
Font[0] = "10px"; //文字的大小
Font[1] = "12px";
Font[2] = "14px";
Font[3] = "16px";
Font[4] = "18px";
setTimeout("strik()",50); }
function strik()
{
for(var i=0;i<strCount;i++)
{
if(typeof(str[i]) != "undefined") //如果字符串存在
{
if(str[i]["Carch"].style.pixelTop > heike.clientHeight)
{
str[i]["Carch"].outerHTML = "";
delete str[i]["Level"]; //删除数组元素
delete str[i]["Speed"];
delete str[i]["Carch"];
delete str[i];
}
else
{
str[i]["Carch"].style.pixelTop += str[i]["Speed"];
}
}
else if(Math.random()<0.25) //随机小数
{
str[i] = new Array();
str[i]["Level"] = Math.round(Math.random()*4);
str[i]["Speed"] = (Math.round(Math.random()*str[i]["Level"]) <<2)+50;
document.all["heike"].insertAdjacentHTML("AfterBegin","<span id='SPAN_"+i+"'>"+sLine+"</span>");
str[i]["Carch"] = document.all["SPAN_"+i];
str[i]["Carch"].style.fontSize = Font[str[i]["Level"]]; //字体
str[i]["Carch"].style.position = "absolute"; //位置
str[i]["Carch"].style.pixelLeft = Math.round(Math.random() *heike.clientWidth); //x坐标
str[i]["Carch"].style.pixelTop = -str[i]["Carch"].offsetHeight; //y坐标
str[i]["Carch"].style.color = Color[str[i]["Level"]+5]; //颜色
str[i]["Carch"].style.filter = "glow(Color="+Color[str[i] ["Level"]]+",Strength=5)"; //滤镜效果
str[i]["Carch"].style.zIndex = str[i]["Level"]; //z-Index
}
}
setTimeout("strik()",50);
}
</script>
<BODY onload="OnLoad()">
<table width="100%" height="100%" border="0" cellspacing="0" cellpadding="0">
<tr><td align="center" height="100%"><div id="heike"></div></td></tr>
<tr><td align="center" style="padding:5;font-size:9pt;color:#FFFFFF;">使用 IE 6.0 以上版本或以IE 为核心的浏览器浏览本页，1024*768分辨率为佳</td></tr>
</table>
</BODY>
</HTML>
提示：重点是对颜色和速度的随机设置。JavaScript中的“Math”对象用来提供数学运算，其中“Math.random”用来获取一个0到1之间的随机数。“Math.round”是采用四舍五入方式取得最接近的整数。代码中使用了两维数组，“delete”方法用来删除数组中的元素。
( 你可以自己去修改参数看看对应的效果，如：JS中关于文字下降速度控制的变量Speed，可以将其调的大一些，让它更快些；还可以修改CSS样式里溢出属性“overflow”取消隐藏，看看有多难看！。。。。。)