Javascript初学者 - 谁能告诉我为什么我的按钮不起作用？

Question

jsfiddle在这里 - ＆gt; http://jsfiddle.net/diabetesjones/015k1tjn/5/

这是一个有效的例子： http://jsfiddle.net/Ahopefulmachine/dkhj8o38/

关于第二个jsfiddle（不是我的），我不太明白为什么他的作品没有在按钮上使用document.getElementById。

我觉得我的问题出在点击功能本身：

document.getElementById('mainButton').onclick = function () {

谢谢：）

Answer 1

立即开始工作：http://jsfiddle.net/doniyor/015k1tjn/9/

您的document.getElementByID应为document.getElementById

AND

1. 你没有像numberOne = parseInt(numberOne, 10);那样将字符串转换为int，其中10是小数的基数。
2. 您的question == ADD应为question == 'ADD'

Answer 2

您的代码有三个问题：

1. 它是getElementById而非getElementByID（区分大小写）。
2. 您没有将输入的字符串转换为数字。您可以在+
前面添加document.getElementById('number1').value;，轻松完成此操作
3. 您正在对变量进行比较，而不是字符串。前question == ADD代替question == 'ADD'

请参阅更正 jsFiddle example

document.getElementById('mainButton').onclick = function () {

    //Getting values of inputs and saving them to variables
    var numberOne = +document.getElementById('number1').value;
    var numberTwo = +document.getElementById('number2').value;

    //Setting values of the equations
    var addition = (numberOne + numberTwo);
    var subtraction = (numberOne - numberTwo);
    var multiplication = (numberOne * numberTwo);
    var division = (numberOne / numberTwo);

    //Prompting user for their desired equation
    var question = prompt("Do you wish to ADD, SUBTRACT, MULTIPLY, or DIVIDE?").toUpperCase();

    //If statement to show the proper equation based on the user's prior prompt
    if (question == 'ADD') {
        alert('I added the shit out of those numbers for you - turns out it is ' + addition);
    } else if (question == 'SUBTRACT') {
        alert('Did some of this, some of that, some minusing - your answer is ' + subtraction);
    } else if (question == 'MULTIPLY') {
        alert('Yeah, I multipled the numbers, big whoop, wanna fight abouddit? the answers over there --> ' + multiplication);
    } else if (question == 'DIVIDE') {
        alert('This ones my favorite, I love a good division - ' + division);
    };

};