JSFiddle - React, Tailwind, and code Playground

HTML

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

JavaScript

$(document).ready(function() {
  $("#text_box_url").blur(function() {
    var input = $(this);
    var val = input.val();
    if (val && !val.match(/^http([s]?):\/\/.*/||/www/) {
        input.val('http://' + val);
    }
  });
});