Javascript显示和隐藏

Question

How do I make this when I click the header it will hide or show the List? and when its visible the header shows - and when its not visible it shows a +. Thanks a lot

 <div class="RevealCard">
  <h3 class="RevealCard-header">
  Top five loves
  </h3>
  <ol class="RevealCard-list">
  <li>First item</li>
  <li>Second item</li>
  <li>Third item</li>
  <li>Fourth item</li>
  <li>Fifth item</li>
  </ol>
 </div>

Here is the CSS

RevealCard-header {
  background: #000;
  border-radius: 4px 4px 0 0;
  color: #fff;
  font-size: 1.2em;
  font-weight: normal;
  margin: 0;
  padding: 0.5em;
  position: relative;
}

.RevealCard-header::after {
  border: 1px solid #fff;
  content: "-";
  height: 1.15em;
  line-height: 1em;
  position: absolute;
  right: 0.5em;
  text-align: center;
  width: 1.15em;
}

.RevealCard-list {
  border: 1px solid #000;
  border-top: none;
  margin: 0 0 2em 0;
  padding-bottom: 1em;
  padding-top: 1em;
}

Answer 1

Here's a working solution:

 var header = document.getElementsByClassName('RevealCard-header')[0]; var list = document.getElementsByClassName('RevealCard-list')[0]; var collapseChar = document.getElementById('collapseChar'); header.addEventListener('click', function(){ // toggle list on click if (list.style.display.toLowerCase() != "none") { // hide list list.style.display = "none"; collapseChar.innerHTML = "+"; } else { // show list list.style.display = "block"; collapseChar.innerHTML = "−"; } }) 

 RevealCard-header { background: #000; border-radius: 4px 4px 0 0; color: #fff; font-size: 1.2em; font-weight: normal; margin: 0; padding: 0.5em; position: relative; } .RevealCard-header::after { border: 1px solid #fff; content: "-"; height: 1.15em; line-height: 1em; position: absolute; right: 0.5em; text-align: center; width: 1.15em; } .RevealCard-list { border: 1px solid #000; border-top: none; margin: 0 0 2em 0; padding-bottom: 1em; padding-top: 1em; } #collapseChar { margin-right: 3px; } 

 <div class="RevealCard"> <h3 class="RevealCard-header"> <span id="collapseChar">&minus;</span>Top five loves </h3> <ol class="RevealCard-list"> <li>First item</li> <li>Second item</li> <li>Third item</li> <li>Fourth item</li> <li>Fifth item</li> </ol> </div> 

You just have to check to see if the list is visible. If it's not, show it; if it is, hide it.

It's also here as a fiddle, if you want to play around with it.

Answer 2

This should do it:

 function clickDropdown(){ var listitems = document.getElementById("RevealCard"); var header = document.getElementById("RevealCard-header").innerHTML; if(listitems.style.display == "none"){ listitems.style.display = 'block'; header = header.replace('+', '-'); document.getElementById("RevealCard-header").innerHTML = header; }else{ listitems.style.display = 'none'; header = header.replace('-','+'); document.getElementById("RevealCard-header").innerHTML = header; } } 

 RevealCard-header { background: #000; border-radius: 4px 4px 0 0; color: #fff; font-size: 1.2em; font-weight: normal; margin: 0; padding: 0.5em; position: relative; } .RevealCard-header::after { border: 1px solid #fff; content: "-"; height: 1.15em; line-height: 1em; position: absolute; right: 0.5em; text-align: center; width: 1.15em; } .RevealCard-list { border: 1px solid #000; border-top: none; margin: 0 0 2em 0; padding-bottom: 1em; padding-top: 1em; } 

 <div class="RevealCard"> <a onClick="clickDropdown()"> <h3 id="RevealCard-header"> Top five loves + </h3></a> <ol style="display: none;" id="RevealCard"> <li>First item</li> <li>Second item</li> <li>Third item</li> <li>Fourth item</li> <li>Fifth item</li> </ol> </div> 

Answer 3

Not only do you want to toggle the OL element, you also want to change the pseudo ::after css. Easiest way? Create a second css ::after style, and simply toggle them both. See below.

 var myHead = document.getElementsByClassName("RevealCard-header"); for (var i = 0, j = myHead.length; i < j; i++) { myHead[i].addEventListener("click", function() { var myTab = this.parentNode.querySelector("ol"); if (myTab.style.display == "") { // Because of the pseudo ::after el, we'll // create a showing/hiding class. this.classList.remove("header-showing"); this.classList.add("header-hiding"); myTab.style.display = "none" } else { this.classList.remove("header-hiding"); this.classList.add("header-showing"); myTab.style.display = ""; } }) } 

 .RevealCard { width: 45%; float: left; padding: 5px; } .RevealCard-header { background: #000; border-radius: 4px 4px 0 0; color: #fff; font-size: 1.2em; font-weight: normal; margin: 0; padding: 0.5em; position: relative; } .header-showing::after { border: 1px solid #fff; content: "-"; height: 1.15em; line-height: 1em; position: absolute; right: 0.5em; text-align: center; width: 1.15em; } .header-hiding::after { border: 1px solid #fff; content: "+"; height: 1.15em; line-height: 1em; position: absolute; right: 0.5em; text-align: center; width: 1.15em; } .RevealCard-list { border: 1px solid #000; border-top: none; margin: 0 0 2em 0; padding-bottom: 1em; padding-top: 1em; } 

 <div class="RevealCard"> <h3 class="RevealCard-header header-showing"> Top five loves </h3> <ol class="RevealCard-list"> <li>First item</li> <li>Second item</li> <li>Third item</li> <li>Fourth item</li> <li>Fifth item</li> </ol> </div> <div class="RevealCard"> <h3 class="RevealCard-header header-showing"> Another five loves </h3> <ol class="RevealCard-list"> <li>First item</li> <li>Second item</li> <li>Third item</li> <li>Fourth item</li> <li>Fifth item</li> </ol> </div> 

Updated to support multiple sets. You do this by attaching the listener to the head, then working within its own parent's DOM structure.