JSFiddle - React, Tailwind, and code Playground
HTML
<label id='label_cep' for='cep'>CEP</label>
<input alt='cep' class='text difCep' name='cep' id='cep' type='text' />
<button type='button' onclick='alert("O valor de CEP Ă©: " + document.getElementById("cep").value)' style="padding: 6px; height: 24px; margin-left: 10px;">Buscar</button>