<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>01元素绑定事件</title>
</head>
<body>
<input type="text" id="oneTXT" />
<input type="button" id="btn" value="计算"/>
</body>
<script type="text/javascript">
//通过id 获取页面元素
var oneBtn = document.getElementById("btn");
var oneTXT = document.getElementById("oneTXT");
//给元素绑定点击事件
oneBtn.onclick = function(){
//将输入框中的值 转换为整数
var val = oneTXT.value - 0;
//20美元个数
var con20 = Math.floor(val / 20);
//10美元个数
var con10 = Math.floor(val % 20 / 10);
//5美元个数
var con5 = Math.floor(val % 20 % 10 /5);
//1美元个数
var con1 = Math.floor(val %20 % 10 % 5);
//输出结果
alert(con20 + "个美元," + con10 + "个美元," + con5 + "个美元," + con1 +"个美元,")
}
</script>
</html>