老师帮我检查一下作业

来源：4-14 项目作业

艳艳子

2022-06-30 18:20:46

<!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>Document</title>
</head>
<body>
    <input type="text" id="num1">
    <select name="" id="operate">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="*">*</option>
        <option value="/">/</option>
    </select>
    <input type="text" id="num2">
    <input type="button" value="=" id="btn">
    <input type="text" id="result">
    <script>
        var num1=document.getElementById('num1');
        var num2=document.getElementById('num2');
        var operate=document.getElementById('operate');
        var result=document.getElementById('result');
        var btn=document.getElementById('btn');
        btn.onclick=function(){
            if(operate.value=='+'){
               result.value=Number(num1.value)+Number(num2.value);
            }
            else if(operate.value=='-'){
               result.value=Number(num1.value)-Number(num2.value);
            }
            else if(operate.value=='*'){
              result.value=Number(num1.value)*Number(num2.value);
            }
            else{
               result.value=Number(num1.value)/Number(num2.value);
            }
        }

    </script>
</body>
</html>

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