复制到剪贴板不起作用

Question

我在codepen上复制的示例工作正常：http://codepen.io/SitePoint/pen/vNvEwE

<label for="website">Website:</label>
<input type="text" id="website" value="http://www.sitepoint.com/" />
<button data-copytarget="#website">copy</button>

<label for="twitter">Twitter:</label>
<input type="text" id="twitter" value="http://twitter.com/craigbuckler" />
<button data-copytarget="#twitter">copy</button>

/*
    Copy text from any appropriate field to the clipboard
  By Craig Buckler, @craigbuckler
  use it, abuse it, do whatever you like with it!
*/
(function() {

    'use strict';

  // click events
  document.body.addEventListener('click', copy, true);

    // event handler
    function copy(e) {

    // find target element
    var 
      t = e.target,
      c = t.dataset.copytarget,
      inp = (c ? document.querySelector(c) : null);

    // is element selectable?
    if (inp && inp.select) {

      // select text
      inp.select();

      try {
        // copy text
        document.execCommand('copy');
        inp.blur();

        // copied animation
        t.classList.add('copied');
        setTimeout(function() { t.classList.remove('copied'); }, 1500);
      }
      catch (err) {
        alert('please press Ctrl/Cmd+C to copy');
      }

    }

    }

})();

当我在localhost上编写代码或上传到我的服务器时，它不起作用。我很确定我正在复制它。

http://loverant.com/bootstraptest/

我对编码很陌生，所以我可能只是错过了一些非常愚蠢的东西。