title: jQuery addClass() not working in PHP which includes header.php which loads jQuery
body: <p>As the title, addClass() does not work in this php file.</p>
  
  <p><a href="http://wafflemaker.kr/ykrf/forum2011/forum2011.php" rel="nofollow">http://wafflemaker.kr/ykrf/forum2011/forum2011.php</a></p>
  
  <pre><code>    &lt;h3 class="fs12 read-more-toggle ti20"&gt;Read more&lt;/h3&gt;
      &lt;script type="text-javascript"&gt;
      $(document).ready(function(){
              $('.read-more-content').addClass('hide');
              // Set up the toggle.
              $('.read-more-toggle').on('click', function() {
                $(this).next('.read-more-content').toggleClass('hide');
              }); 
      }); 
      &lt;/script&gt;       
      &lt;div class="read-more-content pd20" style="border: 1px dotted #444444;"&gt;
          &lt;p class="fs12 al_justify"&gt;Recent years, natural and men-made disasters are frequently  attacking almost all around the world. Disasters occured in our three countries recently are driving more and more people' s attention to the precaution and emergence responses.&lt;/p&gt;
  </code></pre>
  
  <p>class "hide" means display:none, and it is well defined in the CSS.
  At the top of forum2011.php, it includes header2.php which has the line </p>
  
  <pre><code>    &lt;script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js?ver=3.2.1"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="http://wafflemaker.kr/ykrf/js/ui/jquery.effects.core.min.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="http://wafflemaker.kr/ykrf/js/ui/jquery.ui.core.min.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>jQuery functions that apply to elements in header2.php work well, but not at all to elements in forum2011.php. </p>
  
  <p>Is this because jQuery script tag in one page does not reach the page which included it?
  also, now I already have $(document).ready() in header2.php. Is it a problem to use another $(document).ready() in forum2011.php as well? </p>