JSFiddle - React, Tailwind, and code Playground
HTML
<button class="myBtn myBtnCTA signIn" onclick="javascript:;">
<span>Close</span>
</button>
JavaScript
alert($('button.myBtn.myBtnCTA.signIn span').text());
<button class="myBtn myBtnCTA signIn" onclick="javascript:;">
<span>Close</span>
</button>
alert($('button.myBtn.myBtnCTA.signIn span').text());