<!DOCTYPE html>
<html>
<head>
<title>计算器</title>
<meta charset="utf-8" />
<style type="text/css">
.panel {
border: 4px solid #ddd;
width: 192px;
margin: 100px auto;
border-radius: 6px;
}
.panel p, .panel input {
font-family: "微软雅黑";
font-size: 20px;
margin: 4px;
float: left;
border-radius: 4px;
}
.panel p {
width: 122px;
height: 26px;
border: 1px solid #ddd;
padding: 6px;
overflow: hidden;
}
.panel input {
width: 40px;
height: 40px;
border:1px solid #ddd;
}
</style>
<script type="text/javascript">
function cal(e){
//1.获取时间源(button,p,div)
var obj=e.srcElement||e.target;
//2.只处理按钮button事件,节点名大写
if(obj.nodeName!="INPUT"){
return;
}
//3.判断按钮的类型(value)做不同的处理
var p=document.getElementById("screen");
var val=obj.value;
if(val=="C"){
//清屏
p.innerHTML="";
}else if(val=="="){
//计算
try{
var r=eval(p.innerHTML);
p.innerHTML=r;
}catch(e){
//错误时提示
p.innerHTML="Error";
}
}else{
//累加
p.innerHTML+=val;
}
}
</script>
</head>
<body>
<div class="panel" onclick="cal(event);">
<div>
<p id="screen"></p>
<input type="button" value="C">
<div style="clear:both"></div>
</div>
<div>
<input type="button" value="7">
<input type="button" value="8">
<input type="button" value="9">
<input type="button" value="/">
<input type="button" value="4">
<input type="button" value="5">
<input type="button" value="6">
<input type="button" value="*">
<input type="button" value="1">
<input type="button" value="2">
<input type="button" value="3">
<input type="button" value="-">
<input type="button" value="0">
<input type="button" value=".">
<input type="button" value="=">
<input type="button" value="+">
<div style="clear:both"></div>
</div>
</div>
</body>
</html>
图片示例

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