我一直在自学一些 Javascript；而且我无法使此功能正常运行。 这就是正在输出的内容。
答案:[对象 HTMLInputElement][对象 HTMLInputElement]
function addNumbers() {
var firstNum = document.getElementById("num1");
var secondNum = document.getElementById("num2");
result = firstNum + secondNum;
document.getElementById("demo").innerHTML = "Answer: " + result;
return result;
}<!DOCTYPE html>
<html>
<head>
<!-- ,<script src="scripts.js"></script> -->
</head>
<body>
<h2>JavaScript Functions</h2>
<p>This example calls a function which performs a calculation and returns the result:</p>
<form>
First Number<br>
<input type="text" name="firstNum" id="num1"><br> Second Number<br>
<input type="text" name="secondNum" id="num2"><br>
<input type="button" value="Add!" onclick="addNumbers()">
</form>
<p id="demo"></p>
</body>
</html>最佳答案
如评论所说，从HTML元素节点中获取值并解析成float
var firstNum = parseFloat(document.getElementById("num1").value);
var secondNum = parseFloat(document.getElementById("num2").value);
function addNumbers() {
var firstNum = parseFloat(document.getElementById("num1").value);
var secondNum = parseFloat(document.getElementById("num2").value);
result = firstNum + secondNum;
document.getElementById("demo").innerHTML = "Answer: " + result;
return result;
}<!DOCTYPE html>
<html>
<head>
<!-- ,<script src="scripts.js"></script> -->
</head>
<body>
<h2>JavaScript Functions</h2>
<p>This example calls a function which performs a calculation and returns the result:</p>
<form>
First Number<br>
<input type="text" name="firstNum" id="num1"><br> Second Number<br>
<input type="text" name="secondNum" id="num2"><br>
<input type="button" value="Add!" onclick="addNumbers()">
</form>
<p id="demo"></p>
</body>
</html>关于javascript - 关于简单 Javascript/HTML 的问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55111866/