使用JS写一个计算器练习

来源：互联网发布：ubuntu常用命令编辑：程序博客网时间：2024/05/16 17:52

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>小小计算器</title>
</head>
<body>
<input type="text" id="num1" placeholder="请输入你要算的数字"/>
<select id="num3" name="">
<option selected="selected" value="1">+</option>
<option value="2">-</option>
<option value="3">*</option>
<option value="4">/</option>
<option value="5">%</option>
</select>
<input type="text" id="num2" placeholder="请输入你要算的数字"/>
=
<input type="text" id="num4" placeholder="结果"/>
<button onclick="calc()">开始计算</button>
</body>
<script type="text/javascript">
function calc(){
var num1=Number(document.getElementById('num1').value);
var num3=document.getElementById('num3').value;
var num2=Number(document.getElementById('num2').value);
var num4=document.getElementById('num4');
switch(num3){
case '1':
num4.value=num1+num2;
break;
case '2':
num4.value=num1-num2;
break;
case '3':
num4.value=num1*num2;
break;
case '4':
num4.value=num1/num2;
break;
case '5':
num4.value=num1%num2;
break;
}
}
</script>
</html>

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