Getting data attribute from class with JavaScript

Question

I have a number of divs with the same season-list class and each has a data-episode-count data attribute. I need to be able to grab the attribute on click and use that value to hide js-show-more-trigger if the value of the attribute is greater than 6. I'm currently looping through all season-list classes, but not sure how to grab the data attribute from the div:

HTML

<div class="js-season-list-item" id="season-5" style="display: block;">
  <div class="season-list" data-episode-count="3">
    <div class="season-list__item">
      <div class="episode-item">
        <div class="episode-card js-episode-card">
          <div class="episode-card__overlay"><a href="/play/3099013"><span class="play-circle sm" data-play-path="/play/3099013"><svg class="svg svg-play"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/svg/svg-defs.svg#svg-play">svg-play</use></svg></span></a></div>
        </div>
        <div class="episode-details">
          <h1 class="heading md hvy">Episode 1</h1>
          <p></p>
          <p class="runtime">21min</p>
        </div>
      </div>
    </div>
    <div class="season-list__item">
      <div class="episode-item">
        <div class="episode-card js-episode-card">
          <div class="episode-card__overlay"><a href="/play/3099014"><span class="play-circle sm" data-play-path="/play/3099014"><svg class="svg svg-play"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/svg/svg-defs.svg#svg-play">svg-play</use></svg></span></a></div>
        </div>
        <div class="episode-details">
          <h1 class="heading md hvy">Episode 2</h1>
          <p></p>
          <p class="runtime">21min</p>
        </div>
      </div>
    </div>
    <div class="season-list__item">
      <div class="episode-item">
        <div class="episode-card js-episode-card">
          <div class="episode-card__overlay"><a href="/play/3099015"><span class="play-circle sm" data-play-path="/play/3099015"><svg class="svg svg-play"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/svg/svg-defs.svg#svg-play">svg-play</use></svg></span></a></div>
        </div>
        <div class="episode-details">
          <h1 class="heading md hvy">Episode 3</h1>
          <p></p>
          <p class="runtime">21min</p>
        </div>
      </div>
    </div>
  </div>
</div>

JavaScript

let trigger = document.getElementsByClassName('js-show-more-trigger');
let seasonList = document.getElementsByClassName("season-list")
for(let i = 0; i < seasonList.length; i++) {
  if(seasonList[i].getAttribute('data-episode-count') < 6){
    trigger.style.display = "none";
  }
}

Codepen: Link

Answer 1

First and foremost you can check the documentation for better understating.

If I understand you correctly, you want to hide the "Show More" link when the episodeCount > 6, the snippet below is working as intended. Your ifstatement was only hiding the trigger if the value was less then 6.

You can check the behavior by changing the data-episode-count value.

let trigger = document.getElementsByClassName('js-show-more-trigger');
let seasonList = document.getElementsByClassName("season-list")
for(let i = 0; i < seasonList.length; i++) {
  if(seasonList[i].dataset.episodeCount > 6){
    trigger[i].style.display = "none";
  }
}

.season-list{
  display: flex;
}

<div class="js-season-list-item" id="season-5" style="display: block;">
  <div class="season-list" data-episode-count="7">
    <div class="season-list__item">
      <div class="episode-item">
        <div class="episode-card js-episode-card">
          <div class="episode-card__overlay"><a href="/play/3099013"><span class="play-circle sm" data-play-path="/play/3099013"><svg class="svg svg-play"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/svg/svg-defs.svg#svg-play">svg-play</use></svg></span></a></div>
        </div>
        <div class="episode-details">
          <h1 class="heading md hvy">Episode 1</h1>
          <p></p>
          <p class="runtime">21min</p>
        </div>
      </div>
    </div>
    <div class="season-list__item">
      <div class="episode-item">
        <div class="episode-card js-episode-card">
          <div class="episode-card__overlay"><a href="/play/3099014"><span class="play-circle sm" data-play-path="/play/3099014"><svg class="svg svg-play"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/svg/svg-defs.svg#svg-play">svg-play</use></svg></span></a></div>
        </div>
        <div class="episode-details">
          <h1 class="heading md hvy">Episode 2</h1>
          <p></p>
          <p class="runtime">21min</p>
        </div>
      </div>
    </div>
    <div class="season-list__item">
      <div class="episode-item">
        <div class="episode-card js-episode-card">
          <div class="episode-card__overlay"><a href="/play/3099015"><span class="play-circle sm" data-play-path="/play/3099015"><svg class="svg svg-play"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="/svg/svg-defs.svg#svg-play">svg-play</use></svg></span></a></div>
        </div>
        <div class="episode-details">
          <h1 class="heading md hvy">Episode 3</h1>
          <p></p>
          <p class="runtime">21min</p>
        </div>
      </div>
    </div>
  </div>
</div>

<div class="show-more"><span class="js-show-more-trigger">Show 
More</span></div>

Answer 2

With Element.getAttribute()

seasonList[i].getAttribute('data-episode-count');

With HTMLElement.dataset

seasonList[i].dataset.episodeCount;

Answer 3

You can get data in Javascript by dataset property. In your case:

let seasonList = document.getElementsByClassName("season-list")
for(let i = 0; i < seasonList.length; i++) {
  console.log(seasonList[i].dataset.episodeCount)
}