如何将 NaN 替换为 0 或“未找到输入”

Question

我正在尝试用 0 或“未找到输入”一词替换计算器结果中 NaN 的结果。

这是该部分的 Javascript 代码。

// Calculator Functions JavaScript STARTS here
function add() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("result").textContent = num1 + num2;
    }

    function subtract() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("result").textContent = num1 - num2;
    }

    function multiply() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("result").textContent = num1 * num2;
    }

    function divide() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("result").textContent = num1 / num2;
    }
// Calculator Functions JavaScript ENDS here

这是我的该部分的 HTML 代码。

<div id="container">

<h2>Basic Web Calculator</h2>
<input class="instbtn" type="text" id="num1" placeholder="Enter Numbers Here">
<input class="instbtn" type="text" id="num2" placehodler="Enter Numbers Here">
<br>

<button class="calbtn" onclick="add()">Add (+)</button>
<button class="calbtn" onclick="subtract()">Subtract (-)</button>
<button class="calbtn" onclick="multiply()">Multiply (x)</button>
<button class="calbtn" onclick="divide()">Divide (÷)</button>
<br>

<h3>Result: <span id="result"></span></h3>
</div>

Answer 1

我尝试了多种代码，但仍然失败......直到我做了最简单的事情。我添加了|| 0;在答案代码行的末尾。

function add() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("answer").textContent = num1 + num2 || 0;
    }

    function subtract() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("answer").textContent = num1 - num2 || 0;
    }

    function multiply() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("answer").textContent = num1 * num2 || 0;
    }

    function divide() {
        var num1 = parseFloat(document.getElementById("num1").value);
        var num2 = parseFloat(document.getElementById("num2").value);
        document.getElementById("answer").textContent = num1 / num2 || 0;
    }

<div id="container">

<h2>Basic Web Calculator</h2>
<input class="instbtn" type="number" id="num1" placeholder="Enter Numbers Here">
<input class="instbtn" type="number" id="num2" placehodler="Enter Numbers Here">
<br>

<button class="calbtn" onclick="add()">Add (+)</button>
<button class="calbtn" onclick="subtract()">Subtract (-)</button>
<button class="calbtn" onclick="multiply()">Multiply (x)</button>
<button class="calbtn" onclick="divide()">Divide (÷)</button>
<br>

<h3>The Answer Is: <span id="answer"></span></h3>
</div>