ブラウザ側で日時指定で表示・非表示を切り替えるスクリプト ref: http://qiita.com/dribble13/items/3eb39726aba33add6c0a

file0.js

$(document).ready(function() {
  $(".view_timer").each(function(index, target) {
    var startDate = $(this).attr("start_date");
    var endDate = $(this).attr("end_date");
    var nowDate = new Date();

    if (startDate) {
      startDate = new Date(startDate);
    }
    else {
      startDate = nowDate;
    }
    if (endDate) {
      endDate = new Date(endDate);
    }

    if (startDate <= nowDate && (!endDate || nowDate <= endDate)) {
      $(this).show();
    }
    else {
      $(this).hide();
    }
  });
});

file1.html

<span class="view_timer" start_date="2013/9/24 10:00" end_date="2013/9/30 21:00">HogeHogeFugaFuga</span>

file2.html

<span class="view_timer" start_date="2013/9/24 10:00">テスト</span>

file3.html

<span class="view_timer" end_date="2013/9/30 21:00">お試し</span>