JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" value="+" id="b_1">
<div class="content">This is content box.</div>

JavaScript

$(document).ready(function () {
	    var i = 0;
	    $('.content').hide();
	    $('#b_1').click(function () {
	        if (i == 0) {
	            $('.content').slideToggle('slow', function () {
	                $('#b_1').val('-');
	                i = 1;
	            });
	        } else if (i = 1) {
	            $('.content').slideToggle('slow', function () {
	                $('#b_1').val('+');
	                i = 0;
	            });
	        }
	    });
	});