JavaScript - 如何在使用“this”传递的div中定位嵌套（子）div？

Question

当我点击容器div时，我试图更改容器div元素的类和嵌套在其中的几个div元素。我可以成功更改容器元素的类（case_study_section），但不知道如何定位嵌套（子）div元素（case_study_images，case_study_image1，..）。请帮忙。

P.S。：我需要为不同的子元素添加不同的类。所以他们会分别针对他们。

function expandCollapse(case_study_section) {
  var sectionClasses = case_study_section.classList;
  
	var imagesClasses = case_study_section.getElementsByClassName('case_study_images').classList;

  if (sectionClasses.contains("collapsed_section")) {
    sectionClasses.remove("collapsed_section");
    sectionClasses.add("expanded_section");
  } else {
    sectionClasses.remove("expanded_section");
    sectionClasses.add("collapsed_section");
  }
}

.case_study_section {
  width: 100px;
  height: 100px;
}

.collapsed_section {
  background-color: #ff0000;
}

.expanded_section {
  background-color: #000000;
}

<div class="case_study_section collapsed_section" onClick="expandCollapse(this)">

  <div class="case_study_images collapsed_images">

    <div class="case_study_image1">
    </div>

    <div class="case_study_image2">
    </div>

    <div class="case_study_image3">
    </div>

  </div>

</div>

Answer 1

如果您有父母正在寻找一些孩子，您可以：

var elements = case_study_section.querySelectorAll('.case_study_images');

Array.from(elements).forEach(function (child) {
  child.classList.add('a-class');
})

只需使用常规的CSS选择器。

如果您需要为不同的孩子添加不同的课程，您可以：

//somehow map the selector to the classes
//here the object key is the selector,
//the value the classes
var map = {
  '.case_study_image1': ['a-class', 'b-class'],
  '.case_study_image2': ['c-class']
};

//iterate over the keys
Object.keys(map).forEach(function (selector) {
      //get the classes
  var classes = map[selector],
      //get the element
      element = case_study_section.querySelector(selector),
      //get the classList
      cl = element.classList;

  //apply all at once
  cl.add.apply(cl, classes);
});

Answer 2

您可以尝试使用var children = this.getElementsByTagName("div").getElementsByTagName("div")，然后使用该

返回的元素

Answer 3

尝试使用children

  case_study_section.getElementsByClassName('case_study_images')[0].children

或 x.getElementsByClassName()\[0\]

 case_study_section.getElementsByClassName('case_study_images')[0].getElementsByClassName('images classname')[0]

function expandCollapse(case_study_section) {
  var sectionClasses = case_study_section.classList;
  
	var imagesClasses = case_study_section.getElementsByClassName('case_study_images').classList;
  
  console.log(case_study_section.getElementsByClassName('case_study_images')[0].children)

  if (sectionClasses.contains("collapsed_section")) {
    sectionClasses.remove("collapsed_section");
    sectionClasses.add("expanded_section");
  } else {
    sectionClasses.remove("expanded_section");
    sectionClasses.add("collapsed_section");
  }
}

.case_study_section {
  width: 100px;
  height: 100px;
}

.collapsed_section {
  background-color: #ff0000;
}

.expanded_section {
  background-color: #000000;
}

<div class="case_study_section collapsed_section" onClick="expandCollapse(this)">

  <div class="case_study_images collapsed_images">

    <div class="case_study_image1">
    </div>

    <div class="case_study_image2">
    </div>

    <div class="case_study_image3">
    </div>

  </div>

</div>