JSFiddle - React, Tailwind, and code Playground
HTML
<input id="dropUnit" type="text" />
<input id="dropUnit1" disabled type="text" />
JavaScript
alert($('#dropUnit').is(':disabled'));
alert($('#dropUnit1').is(':disabled'));
<input id="dropUnit" type="text" />
<input id="dropUnit1" disabled type="text" />
alert($('#dropUnit').is(':disabled'));
alert($('#dropUnit1').is(':disabled'));