/*
 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();
      }
      catch (err) {
        alert('please press Ctrl/Cmd+C to copy');
      }

    }

  }

})();

var foo = {
  bar: function() { return this.baz; },
  baz: 1
};

// this 指向 arguments
(function() {
  return typeof arguments[0]();
})(foo.bar);

// this 指向 global
typeof (f = foo.bar)();

function f(){ return f; }
new f() instanceof f; // false