How to add one event listener for all buttons

Question

How do I add an event listener to multiple buttons and get the value of each one depending on the one clicked. Eg:

Button1
         


        

Answer 1

Like Lucas's answer, this version will use classes instead of ID to select each button, and it will use a basic for loop.

    Button1


    Button2


    Button3


    Button4

The JS

var buttons = document.querySelectorAll(".btn").length;

for (var i = 0; i < buttons ; i++) {
    document.querySelectorAll(".btn")[i].addEventListener("click", function() {
        alert("Button Clicked");
    });
}