检查父div元素包含类

Question

我在div元素中有一个类。这个div元素存在于另一个div元素中。  如何检查父div元素是否包含该类。要么 如何从父div元素遍历到内部div元素并检查类？

Answer 1

使用> css选择器检查元素是否恰好是另一个元素中的一个级别。

var innerDiv = document.querySelector("#parent_div_id > div > .innerClass");

if(innerDiv) { // yes, it exists!

querySelector docs.

Answer 2

function hasClass(ele, klassName) {
// First we get the value of the ele's class-attribute with `ele.className`.
// That can return an empty string, or one class-name, or several class-names
// separated by spaces. To regard these cases, we pre- and append spaces, before
// checking for the occurence of the passed `klassName` with `indexOf()`.
  return (' ' + ele.className + ' ').indexOf(' ' + klassName + ' ') > -1
}

function firstChildEleHasClass(ele, klassName) {
  ele = ele.firstElementChild
  return hasClass(ele, klassName)
}

function parentEleHasClass(ele, klassName) {
  ele = ele.parentElement
  return hasClass(ele, klassName)
}