计算器app如下：
学习了js和jquery，编写了一个计算器app。主要思路是将按键事件对应字符串存储，利用eval()方法进行执行，需要注意的时执行前要将x替换为*，÷替换为/。另外调整了一些CSS样式，模仿iPhone计算器的界面，源代码看嵌入的网页。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>计算器</title>
<style>
*{margin: 0px;padding: 0px;}
#main{background: #000;border-radius: 30px; height: 500px;width: 220px;margin: auto;}
#result{width: 165px;height: 40px; margin: 60px 0px 5px 25px; border: 0px;
background: #000;color: white;text-align: right;line-height: 40px;font-size: 40px;}
table{background: #000;border-spacing:6px ;margin: auto; }
table input{width:40px ;height: 40px; text-align: center;background: rgb(49, 49, 49);border:solid 0px blac;border-radius: 20px;
color: white;font-size: 20px; line-height: 40px;}
table input:active{background: #fff;color: #000;}
.btnf{background: rgb(246, 153, 6)}
.btnf:active{background: rgb(246, 246, 246);color: rgb(246, 153, 6);}
#cal{background: rgb(183, 45, 26);width: 80px;}
#cal:active{background:rgb(246, 246, 246);color: rgb(183, 45, 26);}
</style>
<script type="text/javascript" src="https://code.jquery.com/jquery-3.1.1.min.js" ></script>
<script>
$(document).ready(function () {
var clickBtn = "0";//结果显示内容 x÷
var calstr = "";//实际计算的内容 */
$(":button").click(function () {
var n = $(this).val();
if (n == 'C') {
clickBtn = "0";
} else if (n == '=') {
try {
var inputText = $("#result").val();
calstr = inputText.replace(/x/g, "*").replace(/÷/g, "/");
clickBtn = window.eval(calstr);
} catch (err) {
clickBtn = "输入错误！";
}
} else if ($("#result").val() == 0 && n != "+" && n != "-" && n != "x" && n != "÷") {
clickBtn = n;
} else {
clickBtn += n;
}
$("#result").val(clickBtn);
});
});
</script>
</head>
<body>
<div id="main">
<input type="text" id="result" value="0" size="17" maxlength="17" >
<table border="0px" >
<tr>
<td><input type="button" class="btn" value="7"></td>
<td><input type="button" class="btn" value="8"></td>
<td><input type="button" class="btn" value="9"></td>
<td><input type="button" id="add" class="btnf" value="+"></td>
</tr>
<tr>
<td><input type="button" class="btn" value="4"></td>
<td><input type="button" class="btn" value="5"></td>
<td><input type="button" class="btn" value="6"></td>
<td><input type="button" id="sub" class="btnf" value="-"></td>
</tr>
<tr>
<td><input type="button" class="btn" value="1"></td>
<td><input type="button" class="btn" value="2"></td>
<td><input type="button" class="btn" value="3"></td>
<td><input type="button" id="times" class="btnf" value="x"></td>
</tr>
<tr>
<td><input type="button" class="btn" value="0"></td>
<td><input type="button" class="btn" id="dot" value="."></td>
<td><input type="button" class="btnf" value="C"></td>
<td><input type="button" class="btnf" id="chu" value="÷"></td>
</tr>
<tr>
<td><input type="button" class="btn" value="("></td>
<td><input type="button" class="btn" value=")"></td>
<td colspan="2"><input type="button" class="btnf" id="cal" value="=" ></td>
</tr>
</table>
</div>
</body>
</html>
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