JSFiddle - React, Tailwind, and code Playground

HTML

<p>Zip Code: <input type="text" id="zip" /></p>
    <p>City: <input type="text" id="city" /></p>
    <p>State: <input type="text" id="state" /></p>

JavaScript

$("#zip").keyup(function() {
	var el = $(this);
	
	if ((el.val().length == 5) && (is_int(el.val()))) {
	    $.ajax({
  	    url: "http://zip.elevenbasetwo.com",
  	    cache: false,
  	    dataType: "json",
  	    type: "GET",
  	    data: "zip=" + el.val(),
        success: function(result, success)

        $("#city").val(result.city);
        $("#state").val(result.state);
        });
    }
});