JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" />
<div class="div">
 
</div>

CSS

.div{
  height:800px;
  width:100%;
  background: red;
}

JavaScript

$('input').focus(function () {
    $(this).attr('class', 'hastext', function(){
    	$('.div').css({
      'backround': 'blue',
      })
    });
});
$('input').blur(function () {
    if($(this).val() == '') {
    $(this).removeAttr('class');
    }
});