Attach event to dynamic elements in javascript

Question

I\'m trying to insert html data dynamically to a list that is dynamically created, but when i try to attach an onclick event for the button that is dynamically created the e

Answer 1

You must attach the event after insert elements, like that you don't attach a global event on your document but a specific event on the inserted elements.

e.g.

document.getElementById('form').addEventListener('submit', function(e) {
  e.preventDefault();
  var name = document.getElementById('txtName').value;
  var idElement = 'btnPrepend';
  var html = `
    <ul>
      <li>${name}</li>
    </ul>
    <input type="button" value="prepend" id="${idElement}" />
  `;
  /* Insert the html into your DOM */
  insertHTML('form', html);
  /* Add an event listener after insert html */
  addEvent(idElement);
});

const insertHTML = (tag = 'form', html, position = 'afterend', index = 0) => {
  document.getElementsByTagName(tag)[index].insertAdjacentHTML(position, html);
}
const addEvent = (id, event = 'click') => {
  document.getElementById(id).addEventListener(event, function() {
    insertHTML('ul', '<li>Prepending data</li>', 'afterbegin')
  });
}

<form id="form">
  <div>
    <label for="txtName">Name</label>
    <input id="txtName" name="txtName" type="text" />
  </div>
  <input type="submit" value="submit" />
</form>

Answer 2

You can do something similar to this:

// Get the parent to attatch the element into
var parent = document.getElementsByTagName("ul")[0];

// Create element with random id
var element = document.createElement("li");
element.id = "li-"+Math.floor(Math.random()*9999);

// Add event listener
element.addEventListener("click", EVENT_FN);

// Add to parent
parent.appendChild(element);

Answer 3

I know that the topic is too old but I gave myself some minutes to create a very useful code that works fine and very easy using pure JAVASCRIPT. Here is the code with a simple example:

String.prototype.addEventListener=function(eventHandler, functionToDo){
  let selector=this;
  document.body.addEventListener(eventHandler, function(e){
    e=(e||window.event);
    e.preventDefault();
    const path=e.path;
    path.forEach(function(elem){
      const selectorsArray=document.querySelectorAll(selector);
      selectorsArray.forEach(function(slt){
        if(slt==elem){
          if(typeof functionToDo=="function") functionToDo(el=slt, e=e);
        }
      });
    });
  });
}

// And here is how we can use it actually !

"input[type='number']".addEventListener("click", function(element, e){
	console.log( e ); // Console log the value of the current number input
});

<input type="number" value="25">
<br>
<input type="number" value="15">
<br><br>
<button onclick="addDynamicInput()">Add a Dynamic Input</button>
<script type="text/javascript">
  function addDynamicInput(){
    const inpt=document.createElement("input");
          inpt.type="number";
          inpt.value=Math.floor(Math.random()*30+1);
    document.body.prepend(inpt);
  }
</script>

Answer 4

This is due to the fact that your element is dynamically created. You should use event delegation to handle the event.

 document.addEventListener('click',function(e){
    if(e.target && e.target.id== 'brnPrepend'){
          //do something
     }
 });

jquery makes it easier:

 $(document).on('click','#btnPrepend',function(){//do something})

Here is an article about event delegation event delegation article