javascript - 如何获取getElementsByClassName()数组的下标？

Question

比如，我用getElementsByClassName()获取了5个标签，我又用this控制了其中第二个标签，如何获取this所指向标签在getElementsByClassName()数组中的位置？

ringa_lee · Answer

更正一个错误，getElementsByClassName() 拿到的结果并不是数组，而 HTMLCollection 对象。

const elements = Array.from(document.getElementsByClassName('.class-name'));

// const elements = Array.prototype.slice.apply(document.getElementsByClassName('.class-name'));

const that = elements[3];

console.log(elements.indexOf(that));

思路是将获取到的 HTMLCollection 对象转换为数组，再使用数组的 indexOf() 方法获取指定元素的索引。

PHP中文网 · Answer

可以设置this.index

`for(var i=0;i


this.index就是这个元素的下标
`

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