/**
 * Displays an announcement if current date is between the start and end dates
 * Container div ID must be 'announcements'
 * Adjust start and end dates in div id, using the same date format. 
 * Can include one or many announcements with individual dates. 
 * Announcement content can be any HTML
 *
 * USAGE:
<div id="announcements" class="announcement">  
  <div id="Dec_10_2009:Mar_19_2010">
    Announcement 1 content
  </div>
  <div id="Jan_01_2010:Jan_31_2010">
    Announcement 2 content
  </div>
</div>
 */
 
function checkAnnc (d) {
  var today = new Date();
  if (d!=undefined) today = Date.parse(d);
  var annp = document.getElementById('announcements');
  if (annp!=undefined) {
    annp.style.display = 'none';
    var annc = annp.getElementsByTagName('div');
    if (annc.length>0) {
      var f = false;
      for (var i=0;i<annc.length;i++) {
        var date1 = Date.parse(annc[i].id.replace(/_/g, ' ').split(':')[0]);
        var date2 = Date.parse(annc[i].id.replace(/_/g, ' ').split(':')[1]);
        if ((date1 > today) || (date2 < today)) {
          annc[i].style.display = 'none';
        } else {
          annc[i].style.display = 'block';
          f = true;
        }
      }
      if (f) {
        annp.style.display = 'block';
      } else {
        annp.style.display = 'none';
      }
    }
  }
}