JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="url" />

JavaScript

$(document).ready(
    function()
    {
       $("#url").change(
           function()
           {
               var textbox = $(this);
               if (textbox.val().indexOf("http://") == 0)
                   textbox.val(textbox.val().substring(7));
           });
    });