title: Detect Enter keypress in html input without jquery
body: <p>I just want to detect the enter input keypress on my android device. I found out that using jquery, we can do like below:</p>
  
  <pre><code>$('#inputText').keypress(function(event) {
  var keycode = event.keyCode || event.which;
  if(keycode == '13') {
      alert('You pressed a "enter" key in somewhere');    
  }
  });
  </code></pre>
  
  <p>But I don't want to use jquery. I want to use the traditional way like using </p>
  
  <blockquote>
    <p>document.getElementById('inputText')</p>
  </blockquote>
  
  <p>But I don't know how to add in the keypress event function. Do you guys have any idea?</p>