如何选择没有特定类别的元素

这将选择第二个

LI

document.querySelector("li:not([class])")

要么

document.querySelector("li:not(.completed):not(.selected)")

例：

// select li which doesn't have a 'class' attribute...console.log(document.querySelector("li:not([class])"))// select li which doesn't have a '.completed' and a '.selected' class...console.log(document.querySelector("li:not(.completed):not(.selected)")) <ul id="tasks">    <li >One Task</li>    <li>Two Task</li>  </ul>