JSFiddle - React, Tailwind, and code Playground

HTML

<select id='mySelectBox'>
<option value="-1"> Please select</option>
<option value="1"> one</option>
<option value="2">two</option>
</select>

CSS

.input-error{
  border: 1px solid red !important;
}

JavaScript

$(document).ready(function(){
	$('#mySelectBox').each(function() {
  	 if($(this).val() == -1)     
     		$(this).addClass('input-error');     
     else
   			$(this).removeClass('input-error');
    });
});