title: Javascript how to listen keyboard shortcut?
body: <p>I try to use javascript listen the shortcut of keyboard, such as "command+shift+4"<br>
  My current solution is : [on Mac]</p>
  
  <pre><code>window.addEventListener('keypress', function(e){
      if (e.shiftKey &amp;&amp; e.metaKey &amp;&amp; e.keyCode == 52) {
          alert("Here it is.");
      }
  }, false);
  </code></pre>
  
  <p>But since the shortcut "command+shift+4" is the default "screenshot" of Mac, so the javascript can not capture it. If I change the 52 to 53, then this code works, but it listens to "command+shift+5".
  <br>
  Is there some solution let javascript listen to the default shortcut of Mac?</p>