alert the buttons text //source https://jsbin.com/fawepetaha

alert-buttons.html

<div class="btns">
    <p>Write JavaScript (using jQuery is fine) so that clicking on any button will cause an alert to popup with the text of the button that was clicked.</p>

    <p>Make sure your solution is as efficient as possible even if there are a lot more <code>button.btn</code>'s added on the page.  Do not use unnecessary event listeners.</p>
  
    <button class="btn">c</button>
    <button class="btn">l</button>
    <button class="btn">o</button>
    <button class="btn">s</button>
    <button class="btn">e</button>
    <button class="btn">.</button>
    <button class="btn">i</button>
    <button class="btn">o</button>
</div>

<script src="https://code.jquery.com/jquery-2.1.4.js"></script>
<script id="jsbin-javascript">
var buttons = document.getElementsByClassName('btn');
function alertText(){
  alert(this.innerHTML);
}
for(var i=0; i<buttons.length;i++){
  buttons[i].addEventListener("click", alertText);
}
</script>


<script id="jsbin-source-javascript" type="text/javascript">var buttons = document.getElementsByClassName('btn');
function alertText(){
  alert(this.innerHTML);
}
for(var i=0; i<buttons.length;i++){
  buttons[i].addEventListener("click", alertText);
}</script>

script.js

var buttons = document.getElementsByClassName('btn');

function alertText(){
  alert(this.innerHTML);
}

for(var i=0; i<buttons.length;i++){
  buttons[i].addEventListener("click", alertText);
}