JSFiddle - React, Tailwind, and code Playground

HTML

<html>
	<head>
		<style>
			.classOne {background-color:red;}
			.classTwo {background-color:blue;}
		</style>
		<script language=javascript type='text/javascript'>
			function all_c(){
				var elements = document.getElementsByClassName('classOne');
				for (var i=0; i<elements.length;i++) {
					elements[i].className = 'classTwo';				  
				 }
			}
		</script>
	</head>
	<body >


	<button onclick="all_c()">change</button>

<div id=main_container ><div class="all_lines classOne" id="title_0" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div class="all_lines classOne" id="title_1" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div class="all_lines classOne" id="title_2" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div class="all_lines classOne" id="title_3" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div class="all_lines classOne" id="title_4" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div class="all_lines classOne" id="title_5" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div class="all_lines classOne" id="title_6" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div class="all_lines classOne" id="title_7" ><span class="titles"  >some title</span> <span class=bls>anything</span><span class=date > 1/1/2013</span></div></br>loren ipsum etc...</br></br><div...