JSFiddle - React, Tailwind, and code Playground

by Jason

HTML

<div class="form-group " id="requestor_last_name-input">
  <label class="control-label col-sm-2" for="requestor_last_name">Last Name</label>
  <div class="col-sm-10">
    <input type="text" class="form-control" name="requestor_last_name" id="requestor_last_name" size="50" maxlength="50" value="Flaherty" required>
  </div>
</div>

JavaScript

var ast = "<img src='http://images.junostatic.com/landings/lms_register/asterisk.png' alt='required'>";
$("input[required]").parent().prev("label").append(ast);