<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<script>
window.onload = function (){
var oBtn = $('btn');
var num = $('num');
var sum = $('sum');
var olist = $('list');
var min = 0.01;
oBtn.onclick = function (){
if( num.value && sum.value )
{
var oSum = sum.value;
var oNum = num.value;
olist.innerHTML = "";
for(i = 1; i <= oNum;i++){
if( i == oNum )
{
olist.innerHTML += "<li>第"+ i +"个红包，您得到 " + oSum + "元，还剩0元！</li>"
}
else{
var safe_total = (oSum - (oNum - i)*min)/(oNum - i);
var money = (getRandom(+min,+safe_total)).toFixed(2);
oSum = (oSum - money).toFixed(2);
olist.innerHTML += "<li>第"+ i +"个红包，您得到" + money +"元，还剩" + oSum + "元</li>";
}
}
}
}
function $(id) {
return document.getElementById(id);
}
function getRandom(two,one){
return Math.random()*(two-one)+one;
}
}
</script>
<style>
</style>
</head>
<body>
金额：<input id = "sum" type = "text">
数量：<input id = "num" type = "text">
<input id= "btn" type = "button" value= "发红包啦">
<ul id = "list"></ul>
</body>
</html>