JSFiddle - React, Tailwind, and code Playground

HTML

<p><input type='submit' id='submitButton' value='Submit' disabled></p>
<p><button id="convert-table">Convert!</button></p>

JavaScript

function enable(TVD){
		if(TVD >= 800-5 && TVD <= 800 +5){
			$('#submitButton').prop("enabled", true); 	
		}else{
			$('#submitButton').prop("disabled", true);
		 }
		}
    
  $('#convert-table').click(function() {
    var TVD = 800.1
	enable(TVD);
  });