javascript 异步片段

Posted 2021-05-03

// http://www.stevesouders.com/blog/2010/05/11/appendchild-vs-insertbefore/
(function(doc, script) {
  var firstScript = doc.getElementsByTagName(script)[0],
      newScript = doc.createElement(script);

  newScript.type = 'text/javascript';
  newScript.async = true;
  newScript.src = ('https:' == doc.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';

  firstScript.parentNode.insertBefore(newScript, firstScript);
})(document, 'script');

// Minified version
(function (a, b) {
  var c = a.getElementsByTagName(b)[0], d = a.createElement(b);
  d.type = "text/javascript",
  d.async = !0,
  d.src = ("https:" == a.location.protocol ? "https://ssl" : "http://www") + ".google-analytics.com/ga.js",
  c.parentNode.insertBefore(d, c)
})(document, "script");