Button不会链接到Javascript

Question

<div class ="form-group">
    <div class ="form-group">
         <div class="col-xs-8 col-xs-offset-4">
             <input type = "button" value="Play Game" class="btn btn-primary" id="play">
         </div>
    </div>

JavaScript代码

play=document.getElementById("btn-primary");`
play.addEventListener("click", handleAdd, false);

Answer 1

id是'play'，而不是'btn-primary'