javascript - Accordion 列表的加/减图片

Question

下面的代码适用于我使用 HTML、CSS 和 JavaScript 创建的 Accordion 列表。有没有办法在标题的左上角添加加号和减号图片？因此，当我单击标题“A”或“B”时，图片从加号变为减号。这是我想使用的两个图像:

https://www.independencecenter.org/wp-content/uploads/2014/04/wellness.png

https://web.archive.org/web/20150227045704/http://licensing.paperbagrecords.com/wp-content/themes/licensing/assets/images/minus.png

 (function () {
  var accordions, i;
  
  // Make sure the browser supports what we are about to do.
  if (!document.querySelectorAll || !document.body.classList) return;
  
  // Using a function helps isolate each accordion from the others
  function makeAccordion(accordion) {
    var targets, currentTarget, i;
    targets = accordion.querySelectorAll('.accordion > * >h1 ');
    for(i = 0; i < targets.length; i++) {
      targets[i].addEventListener('click', function (e) {
      /*Added the code below*/
        if (e.target.parentNode.classList.contains("expanded")) {
          e.target.parentNode.classList.remove("expanded")
        } else {
        /*Else do the following, same as before */
        if (currentTarget) 
          currentTarget.classList.remove('expanded');
        
        currentTarget = this.parentNode;
        currentTarget.classList.add('expanded');
        }
      }, false);
    }

    accordion.classList.add('js');
  }

  // Find all the accordions to enable
  accordions = document.querySelectorAll('.accordion');
  console.log(accordions);
  
  // Array functions don't apply well to NodeLists
  for(i = 0; i < accordions.length; i++) {
    makeAccordion(accordions[i]);
  }
  
})();

<style>

/*All paragraphs*/

.p {
  margin: 5px;
  color: #007a5e;
}

.bold {
  color: #007a5e;
  font-weight:bold;
  }
  
  .boldwhite {
  font-weight:bold;
  }

/*Accordion Movement*/

.accordion.js > * {
  overflow: hidden;
}

.accordion.js > *:not(.expanded) > *:not(h1) {
  max-height: 0;
  margin-top: 0;
  margin-bottom: 0;
  opacity: 0;
  visibility: hidden;
  overflow: hidden;
}

.accordion.js > .expanded > *:not(h1) {
  opacity: 1;
  visibility: visible;
}

.accordion.js > * > h1 {
  cursor: pointer;
  visibility: visible;
}

.accordion.js > * > *:not(h1) {
  transition: max-height 0.5s, visibility 0.5s, margin 0.5s, opacity 0.5s;
}


/*Section Properties*/

.sections {
  font-family: Verdana;
  font-weight: lighter;
  color: #5E5E5E;
  text-align: center;
  border-style: solid;
  border-width: 1px;
  border-color: #dddddd;
  padding: 5px;
  background-color: #FCFCFC;
  border-radius: 1px;
}

.sections:hover {
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
  -moz-box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  -webkit-box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  -o-box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}


/*Green Section Properties*/

.sections2 {
  font-family: Verdana;
  font-weight: lighter;
  color: #5E5E5E;
  text-align: center;
  border-style: solid;
  border-width: 1px;
  border-color: #ccd6e0;
  padding: 5px;
  background-color:rgba(224, 235, 245,0.3);
  border-radius: 1px;
}

.sections2:hover {
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
  -moz-box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  -webkit-box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  -o-box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.accordion > section > div {
  margin-bottom: 15px;
}
</style>

<section class="accordion js">
    <section class="sections">
        <h1><span style="font-size: 18px;">A</span></h1>
        <div>
            <p class="p" style="text-align: center;"><span style="color: #007a5e;">aerheahqeh.</span></p> 
        </div>
   </section>
   <br style="line-height: 15px;"/>
   <section class="sections2">
      <h1><span style="font-size: 18px;">B</span></h1>
      <div>
         <p class="p" style="text-align: center;">Twtjwrjwrj </p>
      </div>
   </section>
</section>

Answer 1

在扩展类的子类和背景图像上使用伪元素。像这样的东西:

.accordion.js h1{
    position:relative;
}
.accordion.js h1::before{
    content: "";
    display:block;
    height:20px;
    width:20px;
    position:absolute;
    left:0;
    top:0;
    background: url(YourPlusImageUrlHere);
}
.accordion.js .expanded h1::before{
    background: url(YourMinusImageUrlHere);
}

根据您的风格进行调整。