Is using onSubmit and Form-Request or onChange and Ajax-Request more efficient for updating content based on dropdown selection in PHP?

When updating content based on a dropdown selection in PHP, using onChange and Ajax-Request is more efficient than onSubmit and Form-Request. This is because onChange triggers the request immediately when the dropdown value changes, providing a more seamless user experience without the need to submit the entire form. 

<!-- HTML code with dropdown menu -->
<select id="dropdown">
  <option value="1">Option 1</option>
  <option value="2">Option 2</option>
</select>

<!-- Display content here -->
<div id="content"></div>

<script>
  // JavaScript code to handle dropdown change event
  document.getElementById('dropdown').addEventListener('change', function() {
    var selectedValue = this.value;
    
    // Ajax request to fetch updated content based on dropdown selection
    var xhr = new XMLHttpRequest();
    xhr.open('GET', 'update_content.php?selected=' + selectedValue, true);
    xhr.onload = function() {
      if (xhr.status === 200) {
        document.getElementById('content').innerHTML = xhr.responseText;
      }
    };
    xhr.send();
  });
</script>

Keywords

onSubmit Form-Request onChange Ajax-Request dropdown selection

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