How can I get the click event inside an innerHTML?

Question

I've this layout that was created dynamically:

for (let i = 1; i < 10; i++) {
  document.querySelector('.card-body').innerHTML += `<div class="row" id="img_div">
        <div class="col-12 col-sm-12 col-md-2 text-center">
          <img src="http://placehold.it/120x80" alt="prewiew" width="120" height="80">
        </div>
        <div id="text_div" class="col-12 text-sm-center col-sm-12 text-md-left col-md-6">
        <h4 class="name"><a href="#" id="title` + i + `">Name</a></h4>
          <h4>
            <small>state</small>
          </h4>
          <h4>
            <small>city</small>
          </h4>
          <h4>
            <small>zip</small>
          </h4>
        </div>
        <div class="col-12 col-sm-12 text-sm-center col-md-4 text-md-right row">
        </div>
      </div>
     `
  document.getElementById("title" + i).addEventListener('click', function() {
    console.log(i)
  });
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<div class="card-body">
  <!-- person -->
</div>

And I want to get the event click on each h4 class="name" and show a log with the number i related.

However, console.log shows only the last i related (i=9 in this case), and doesn't work with the other i numbers. Why does this happen? What do I have to do?

Answer 1

Using += on innerHTML destroys event listeners on the elements inside the HTML. The correct way to do this is to use document.createElement. Here's a minimal, complete example:

for (let i = 1; i < 10; i++) {
  const anchor = document.createElement("a");
  document.body.appendChild(anchor);
  anchor.id = "title" + i;
  anchor.href= "#";
  anchor.textContent = "link " + i;
  document.getElementById("title" + i)
    .addEventListener("click", e => console.log(i));
}

a {
  margin-left: 0.3em;
}

Of course, the document.getElementById isn't necessary here since we just created the object in the loop block. This saves potentially expensive tree walks.

for (let i = 1; i < 10; i++) {
  const anchor = document.createElement("a");
  document.body.appendChild(anchor);    
  anchor.href= "#";
  anchor.textContent = "link " + i;
  anchor.addEventListener("click", e => console.log(i));
}

a {
  margin-left: 0.3em;
}

If you have arbitrary chunks of stringified HTML as in your example, you can use createElement("div"), set its innerHTML once to the chunk and add listeners as needed. Then append the divs as children of your container element.

for (let i = 1; i < 10; i++) {
  const rawHTML = `<div><a href="#" id="link-${i}">link ${i}</a></div>`;
  const div = document.createElement("div");
  document.body.appendChild(div);
  div.href= "#";
  div.innerHTML = rawHTML;
  div.querySelector(`#link-${i}`)
    .addEventListener("click", e => console.log(i));
}

Answer 2

innerHTML redraws the full html, as a result all the previously attached events are lost. Use insertAdjacentHTML()

for(let i=1;i<10;i++){
    document.querySelector('.card-body').insertAdjacentHTML('beforeend',`<div class="row" id="img_div">
        <div class="col-12 col-sm-12 col-md-2 text-center">
          <img src="http://placehold.it/120x80" alt="prewiew" width="120" height="80">
        </div>
        <div id="text_div" class="col-12 text-sm-center col-sm-12 text-md-left col-md-6">
        <h4 class="name"><a href="#" id="title`+i+`">Name</a></h4>
          <h4>
            <small>state</small>
          </h4>
          <h4>
            <small>city</small>
          </h4>
          <h4>
            <small>zip</small>
          </h4>
        </div>
        <div class="col-12 col-sm-12 text-sm-center col-md-4 text-md-right row">
        </div>
      </div>
     `);
   document.getElementById("title"+i).addEventListener('click', function () {
    console.log(i)
  });
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<div class="card-body">
<!-- person -->
</div>