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用javascript加减乘除

2024-09-10 18:31:30   217人阅读

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>

    </style>
</head>
<body>
<div>
    <input type="text" size="10" id="num1" />
    <select name="sel" id="sel">
        <option>+</option>
        <option>-</option>
        <option>*</option>
        <option>/</option>
        <option>%</option>
    </select>
    <input type="text" size="10" id="num2" />
    <button onclick="myadd()">=</button>
    <input type="text" size="10" id="num3" readonly />
    <div id="div11" style="color: red; font-size: 12px;" >

    </div>
</div>
<script>
    function myadd(){
        var div11 = document.getElementById(‘div11‘);
        var num1 = document.getElementById(‘num1‘);
        var num2 = document.getElementById(‘num2‘);
        var num3 = document.getElementById(‘num3‘);
        var sel = document.getElementById(‘sel‘);

        div11.innerHTML = "";
        if(num1.valuehttp://www.mamicode.com/=="" || isNaN(num1.value) || num2.valuehttp://www.mamicode.com/=="" || isNaN(num2.value)){
            div11.innerHTML = ‘输入的内容不是数字‘;
        }else{
            if(sel.value=http://www.mamicode.com/=‘+‘){
                num3.value = http://www.mamicode.com/(parseFloat(num1.value) + parseFloat(num2.value)).toFixed(2);
            }else if(sel.value=http://www.mamicode.com/=‘-‘){
                num3.value = http://www.mamicode.com/(parseFloat(num1.value) - parseFloat(num2.value)).toFixed(2);
            }else if(sel.value=http://www.mamicode.com/=‘*‘){
                num3.value = http://www.mamicode.com/(parseFloat(num1.value) * parseFloat(num2.value)).toFixed(2);
            }else if(sel.value=http://www.mamicode.com/=‘/‘){
                if(parseFloat(num2.value)==0){
                    div11.innerHTML = ‘被除数不能为0‘;
                }else{
                    num3.value = http://www.mamicode.com/(parseFloat(num1.value) / parseFloat(num2.value)).toFixed(2);
                }
            }else if(sel.value=http://www.mamicode.com/=‘%‘){
                if(parseFloat(num2.value)==0){
                    div11.innerHTML = ‘被除数不能为0‘;
                }else{
                    num3.value = http://www.mamicode.com/(parseFloat(num1.value) % parseFloat(num2.value)).toFixed(2);
                }
            }
        }
    }
</script>
</body>
</html>

用javascript加减乘除


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