As already mentioned, Chrome Extensions don't allow to have inline JavaScript due to security reasons so you can try this workaround as well.
HTML file
<!doctype html>
<html>
<head>
<title>
Getting Started Extension's Popup
</title>
<script src="popup.js"></script>
</head>
<body>
<div id="text-holder">ha</div><br />
<a class="clickableBtn">
hyhy
</a>
</body>
</html>
<!doctype html>
popup.js
window.onclick = function(event) {
var target = event.target ;
if(target.matches('.clickableBtn')) {
var clickedEle = document.activeElement.id ;
var ele = document.getElementById(clickedEle);
alert(ele.text);
}
}
Or if you are having a Jquery file included then
window.onclick = function(event) {
var target = event.target ;
if(target.matches('.clickableBtn')) {
alert($(target).text());
}
}