javascript - 评估语句中的按钮文本

Question

您好，我试图在语句中评估按钮的文本内容，但实际上什么也没发生。

我的 HTML:

<div class="app">
    <h2 id="question"></h2>
    <button class="options" type="button" value="val"><span></span></button>
    <button class="options" type="button" value="val"><span></span></button>
    <button class="options" type="button" value="val"><span></span></button>
    <button class="options" type="button" value="val"><span></span></button>
    </br>
    <button id="submit" type="button" name="button">Submit</button>
    <button id="back" type="button" name="button">Back</button>
</div>

function evaluate() {
    // click the submit button
    submitBtn.addEventListener('click', function() {
        //check if the selected answer is correct
        for(i = 0; i < options.length; i++) {
            if(options[i].classList.contains('picked').textContent === 6) {
                alert('welldone')
            }
        }
    })
}

Answer 1

如果您尝试同时比较按钮文本和类，您可以使用下面的代码。请注意，您使用的 === 也会比较数据类型，因此请将 6 更改为 '6' 或更改比较运算符从 === 到 ==。检查此链接以获取有关 Comparison Operators 的详细信息

 $(document).ready(function () {
        var submitBtn = document.getElementById("submit");
        submitBtn.addEventListener('click', function () {
            //check if the selected answer is correct
            var options = document.querySelectorAll('.options');
            for (i = 0; i < options.length; i++) {
                if (options[i].classList.contains('picked') && options[i].textContent === "6") {
                    alert('welldone')
                }
            }
        });
        });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
<div class="app">
    <h2 id="question"></h2>
    <button class="options picked" type="button" value="val"><span>6</span></button>
    <button class="options" type="button" value="val"><span></span></button>
    <button class="options" type="button" value="val"><span></span></button>
    <button class="options" type="button" value="val"><span></span></button>
    </br>
    <button id="submit" type="button" name="button">Submit</button>
    <button id="back" type="button" name="button">Back</button>
</div>