效果图：
代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
/* Basic Reset */
* {
border: none;
font-family: 'Open Sans', sans-serif;
margin: 0;
padding: 0;
}
body {}
.center {
background-color: #fff;
border-radius: 50%;
height: 600px;
margin: auto;
600px;
}
h1 {
color: #495678;
font-size: 30px;
margin-top: 20px;
padding-top: 50px;
display: block;
text-align: center;
text-decoration: none;
}
a {
color: #495678;
font-size: 30px;
display: block;
text-align: center;
text-decoration: none;
padding-top: 20px;
}
form {
background-color: #495678;
box-shadow: 4px 4px #3d4a65;
margin: 40px auto;
padding: 40px 0 30px 40px;
280px;
}
.btn {
outline: none;
cursor: pointer;
font-size: 20px;
height: 45px;
margin: 5px 0 5px 10px;
45px;
}
.btn:first-child {
margin: 5px 0 5px 10px;
}
.btn,
#display,
form {
border-radius: 25px;
}
#display {
outline: none;
background-color: #98d1dc;
box-shadow: inset 6px 6px 0px #3facc0;
color: #000000;
font-size: 20px;
height: 47px;
text-align: right;
165px;
padding-right: 10px;
margin-left: 10px;
}
.number {
background-color: #72778b;
box-shadow: 0 5px #5f6680;
color: #dededc;
}
.number:active {
box-shadow: 0 2px #5f6680;
-webkit-transform: translateY(2px);
-ms-transform: translateY(2px);
-moz-tranform: translateY(2px);
transform: translateY(2px);
}
.operator {
background-color: #dededc;
box-shadow: 0 5px #bebebe;
color: #72778b;
}
.operator:active {
box-shadow: 0 2px #bebebe;
-webkit-transform: translateY(2px);
-ms-transform: translateY(2px);
-moz-tranform: translateY(2px);
transform: translateY(2px);
}
.other {
background-color: #e3844c;
box-shadow: 0 5px #e76a3d;
color: #dededc;
}
.other:active {
box-shadow: 0 2px #e76a3d;
-webkit-transform: translateY(2px);
-ms-transform: translateY(2px);
-moz-tranform: translateY(2px);
transform: translateY(2px);
}
</style>
</head>
<body>
<div class="center">
<h1>HTML CSS, JavaScript 计算器</h1>
<a href="https://github.com/guuibayer/simple-calculator" target="_blank"><i class="fa fa-github"></i></a>
<form name="calculator">
<input type="button" id="clear" class="btn other" value="C">
<input type="text" id="display">
<br>
<input type="button" class="btn number" value="7" onclick="get(this.value);">
<input type="button" class="btn number" value="8" onclick="get(this.value);">
<input type="button" class="btn number" value="9" onclick="get(this.value);">
<input type="button" class="btn operator" value="+" onclick="get(this.value);">
<br>
<input type="button" class="btn number" value="4" onclick="get(this.value);">
<input type="button" class="btn number" value="5" onclick="get(this.value);">
<input type="button" class="btn number" value="6" onclick="get(this.value);">
<input type="button" class="btn operator" value="*" onclick="get(this.value);">
<br>
<input type="button" class="btn number" value="1" onclick="get(this.value);">
<input type="button" class="btn number" value="2" onclick="get(this.value);">
<input type="button" class="btn number" value="3" onclick="get(this.value);">
<input type="button" class="btn operator" value="-" onclick="get(this.value);">
<br>
<input type="button" class="btn number" value="0" onclick="get(this.value);">
<input type="button" class="btn operator" value="." onclick="get(this.value);">
<input type="button" class="btn operator" value="/" onclick="get(this.value);">
<input type="button" class="btn other" value="=" onclick="calculates();">
</form>
</div>
</body>
</html>
<script type="text/javascript">
/* limpa o display */
document.getElementById("clear").addEventListener("click", function() {
document.getElementById("display").value = "";
});
/* recebe os valores */
function get(value) {
document.getElementById("display").value += value;
}
/* calcula */
function calculates() {
var result = 0;
result = document.getElementById("display").value;
document.getElementById("display").value = "";
document.getElementById("display").value = eval(result);
};
</script>