JavaScript事件
2017年8月2日总结
一个小案例
计算器
<!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>
window.onload = function(){
var calculator = document.getElementById("calculator");
calculator.onclick = function(e){
var input = e.srcElement || e.targer;
if(input.nodeName=="INPUT"){
var p = document.getElementById("screen");
if(input.value=="C"){
p.innerHTML = "";
}else if(input.value=="="){
try{
p.innerHTML = eval(p.innerHTML);
}catch(ex){
p.innerHTML = "输入有误";
}
}else{
p.innerHTML += input.value;
}
}
}
}
</script>
</head>
<body>
<div class="panel" id="calculator">
<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>
网页运行结果