JavaScript生成的动态下雨背景效果实现方法

2019-11-20 13:07:06

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本文实例讲述了JavaScript生成的动态下雨背景效果实现方法。分享给大家供大家参考。具体实现方法如下：

<HTML>
<HEAD>
<TITLE>JavaScript生成的动态下雨背景效果</TITLE>
</HEAD>
<BODY bgcolor="#fef4d2" >
<center>
<script language=JavaScript>

var rainsize = 40;

var speed = 10;
var x = new Array();
var y = new Array();
var r = new Array();
var cx = new Array();
var cy = new Array();
var doc_width = document.body.clientWidth;
var doc_height = document.body.clientHeight;

for(i=0; i<rainsize; ++i) {
initRain();
if (i == 0) {
    document.write("<div id=/"dot"+ i +"/" style=/"POSITION: ");
    document.write("absolute; Z-INDEX: "+ i +"; VISIBILITY: ");
    document.write("visible; TOP: 15px; LEFT: 15px;/"><font color=/"blue/">");
    document.write(",</font></div>"); }
else {
    document.write("<div id=/"dot"+ i +"/" style=/"POSITION: ");
    document.write("absolute; Z-INDEX: "+ i +"; VISIBILITY: ");
    document.write("visible; TOP: 15px; LEFT: 15px;/"><font color=/"blue/">");
    document.write(",.</font></div>"); }
}

function initRain() {
a = 6;
r[i] = 1;
sn = Math.sin(a);
cs = Math.cos(a);
cx[i] = Math.random() * doc_width + 1;
cy[i] = Math.random() * doc_height + 1;
x[i] = r[i] * sn + cx[i];
y[i] = cy[i];
}