Entrada aleatoria en Blogger

<script type='text/javascript'>
//< ![CDATA[
var _yourBlogUrl = "http://braulioaquino.blogspot.com";
 
function randomPost() {
  var script = document.createElement("script");
  script.setAttribute("type", "text/javascript");
  var theUrl = _yourBlogUrl +"/feeds/posts/summary?alt=json-in-script&callback=getTotalPostsCallback&start-index=1&max-results=1";
  script.setAttribute("src", theUrl);
  document.documentElement.firstChild.appendChild(script);
};
function getTotalPostsCallback(json) {
  var totalResults = json.feed.openSearch$totalResults.$t;
  if (totalResults > 0) {
    getRandomPostNumber(totalResults);
  }
};
function getRandomPostNumber(totalResults) {
  var randomNumber = Math.floor((Math.random() * totalResults) + 1);
  getRandomUrl(randomNumber);
};
function getRandomUrl(randomNumber) {
  var script = document.createElement("script");
  script.setAttribute("type", "text/javascript");
  var theUrl = _yourBlogUrl +"/feeds/posts/summary?alt=json-in-script&callback=getTheUrlCallback&start-index=" + randomNumber + "&max-results=1";
  script.setAttribute("src", theUrl);
  document.documentElement.firstChild.appendChild(script);
};
function getTheUrlCallback(json) {
  var theUrl;
  for(var i = 0; i < json.feed.entry[0].link.length; i++) {
    if (json.feed.entry[0].link[i].rel == "alternate") {
      theUrl = json.feed.entry[0].link[i].href;
      break;
    }
  }
 
  if(theUrl) {
    window.location.href = theUrl;
  }
}
//]]>
</script>