JSFiddle - React, Tailwind, and code Playground

HTML

<div class="editor">Hello <span id="t1">my</span><br>dear <span id="t2">world</span></div>

<button id="test">TEST</button>

CSS

.editor
{
	font-size: 16px;
}
.editor:first-line
{
	font-size: 26px;
}

JavaScript

$(document).ready(function()
{
    $('#test').click(function()
    {
    alert( $('#t1').css('font-size') + ' vs ' + $('#t2').css('font-size') );	
    });
});