<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
function fn(x){
//得到文本框 和 div的元素对象
var i1 = document.getElementById("i1");
var i2 = document.getElementById("i2");
var d1 = document.getElementById("d1");
//switch-case 一般的用它来做值匹配的
switch(x){
case 1://加
d1.innerText =
parseFloat(i1.value)+parseFloat(i2.value);
break;
case 2://减
d1.innerText =
parseFloat(i1.value)-parseFloat(i2.value);
break;
case 3://乘
d1.innerText =
parseFloat(i1.value)*parseFloat(i2.value);
break;
case 4://除
d1.innerText =
parseFloat(i1.value)/parseFloat(i2.value);
break;
}
}
</script>
</head>
<body>
<input type="text" id="i1">
<input type="text" id="i2">
<input type="button" value="加" onclick="fn(1)">
<input type="button" value="减" onclick="fn(2)">
<input type="button" value="乘" onclick="fn(3)">
<input type="button" value="除" onclick="fn(4)">
<div id="d1"></div>
</body>
</html>
