Put fixed text on an input text box

Question

How can I put default text in an HTML text input element which the user can't delete (fixed text at the start of the input).

The second thing what I want is that the cursor will be positioned after this fixed text.

Answer 1

var requiredText = 'https://';
$('#site').on('input', function() {
  if (String($(this).val()).indexOf(requiredText) == -1) {
    $(this).val(requiredText);
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input id="site" />