var NewsDelay=15000;		//Time each story is displayed for
var NewsStory=0;		//Working Variable
var v_content;

var running = true;
var timerID = 0;

function DisplayNews()
{
  if (running = true)
  {
    NewsStory++;
    if(NewsStory>=v_content.length)
    {
      NewsStory=0;
    }
    FadeNews();
  }
}

function playNews()
{
  NewsStory++;
  if(NewsStory>=v_content.length)
  {
    NewsStory=0;
  }
  running = true;
  var stext = '<a href="javascript:stopNews();">暂停</a>'
  $('stext').innerHTML=stext;
  FadeNews();
}

function stopNews()
{
  clearTimeout(timerID);
  running = false;
  var stext = '<a href="javascript:playNews();">播放</a>'
  $('stext').innerHTML=stext;
}


function FadeNews()
{
  var NewsText = '<a href="'+ v_content[NewsStory][0] +
    '" class="newsitem" target="_blank" >'+ v_content[NewsStory][1] +'</a>';
  $('newslayer').innerHTML=NewsText;
  timerID = setTimeout('DisplayNews()',NewsDelay);
}

function previousNews()
{
  clearTimeout(timerID);
  NewsStory--;
  if (NewsStory < 0)
  {
    NewsStory = v_content.length-1;
  }
  LastNewsStory=NewsStory-1;
  showSingleNews();
  if (running == true)
  {
    timerID = setTimeout('DisplayNews()', NewsDelay);
  }
}

function nextNews()
{
  clearTimeout(timerID);
  LastNewsStory=NewsStory;
  NewsStory++;
  if(NewsStory>=v_content.length)
  {
    NewsStory=0;
  }
  showSingleNews();
  if (running == true)
  {
    timerID = setTimeout('DisplayNews()', NewsDelay);
  }
}

function showSingleNews()
{
  var NewsText = '<a href="'+ v_content[NewsStory][0] +
    '" class="newsitem" target="_blank" >'+ v_content[NewsStory][1] +'</a>';
  $('newslayer').innerHTML=NewsText;
}
  

function handleHttpResponse()
{
  if (http.readyState == 4)
  {
    if (http.responseText.indexOf('invalid') == -1)
    {
      var xmlDocument = http.responseXML;
      var titles = xmlDocument.getElementsByTagName('title');
      var links = xmlDocument.getElementsByTagName('link');
      var descs = xmlDocument.getElementsByTagName('description');
      var times = xmlDocument.getElementsByTagName('time');
      var i;
      var contents = xmlDocument.getElementsByTagName('content');
      v_content = new Array(titles.length);
      for (i=0; i < titles.length; i++)
      {
        var this_title = titles[i].firstChild.data;
        var this_link = links[i].firstChild.data;
        var this_desc = descs[i].firstChild.data;
        var this_time = times[i].firstChild.data;
        var this_content = "<b>" + this_time + "：" + this_title + "</b><br />" + this_desc;
        v_content[i] = new Array (this_link, this_content, '_blank');
      }
    }
    DisplayNews();

  }
}
var isWorking = false;

function showNews()
{
  if (!isWorking && http)
  {
    var url;
    url = "api/news.php";
    http.open("GET", url, true);
    $('newslayer').innerHTML = 
      '<img src="images/loading.gif" alt="加载中" />正在从互联网上搜索新闻……<br /><br />';
    http.onreadystatechange = handleHttpResponse;
    isWorking = true;
    http.send(null);
  }
  
}

function getHTTPObject()
{
  var xmlhttp;
  /*@cc_on
  @if (@_jscript_version >= 5)
    try
    {
      xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    }
    catch (e)
    {
      try
      {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
      }
      catch (E)
      {
        xmlhttp = false;
      }
    }
  @else xmlhttp = false;
  @end @*/
  if (!xmlhttp && typeof XMLHttpRequest != 'undefined')
  {
    try
    {
      xmlhttp = new XMLHttpRequest();
    }
    catch (e)
    {
      xmlhttp = false;
    }
  }
  return xmlhttp;
}

var http = getHTTPObject(); // We create the HTTP Object