＆＃34;。检查＆＃34;用于JS中的广播

Question

这是我的代码：

document.getElementById("frequencyweekly").checked = function() {
    document.getElementById("newsoptions").className = "activesubscription";
};

    <div id="newsoptions">
        <input type="radio" id="frequencyweekly" name="newsletterfrequency">
        <label for="frequencyweekly">Weekly</label>

        <input type="radio" id="frequencymonthly" name="newsletterfrequency">
        <label for="frequencymonthly">Monthly</label>
    </div>

如果选中#frequencyweekly按钮，我希望我的.newsoptions div有class .activesubscription。我该怎么做？

Answer 1

checked是一个布尔值，而不是一个触发函数的事件，所以你可能想要

if ( document.getElementById("frequencyweekly").checked ) {
    document.getElementById("newsoptions").className = "activesubscription";
}

如果你想在事件处理程序中使用它，那么

var box  = document.getElementById("frequencyweekly"),
    elem = document.getElementById("newsoptions");

box.addEventListener('change', function() {
    if ( this.checked ) {
        elem.classList.add("activesubscription");
    } else {
        elem.classList.remove("activesubscription");
    }
}, false);

Answer 2

如果您想在点击框时执行某些操作，请使用onclick属性。在其中，您可以查看checked属性。

document.getElementById("frequencyweekly").onclick = function() {
    if (this.checked) {
        document.getElementById("newsoptions").className = "activesubscription";
    } else {
        document.getElementById("newsoptions").className = "";
    }
}