JSFiddle - React, Tailwind, and code Playground
HTML
<input id="email" />
<label for="sendCopy">
<input id="sendCopy" type="checkbox" checked="" name="copy"></input>
Send copy to my mail
</label>
JavaScript
$("#email").keyup(function () {
var textNodes= $('label[for="sendCopy"]').contents().filter(function() {
return this.nodeType == 3;
});
textNodes[textNodes.length -1].nodeValue = 'Send copy to my mail: ' + $(this).val();
});