title: Firefox 38-40 SMIL problems - very slow speed (resolved in FF version 41 from 22.09.15)
body: <p>Can you give some information about new versions FF, that passed after version 37.0.2.
  I knew that most of the bugs in version 38 have been fixed in version 38.0.5.
  I noticed a difference in the processing speed of the attributes 'animate' and 'animateTransform' in all new versions of FF, and because of this the page becomes really slow. If remove animate tags:</p>
  
  <pre><code>        &lt;rect x="-1.32" y="-0.63" width="3.64" height="1.26" fill="#FFD9D9" stroke-width="0.0" rx="0.12"&gt;
              &lt;!--this animation makes half-visible selecting effect --&gt;
              &lt;animate attributeType="CSS" attributeName="opacity" to="0.65" dur="0.5s" begin="mouseover" fill="freeze"&gt;&lt;/animate&gt;
              &lt;animate attributeType="CSS" attributeName="opacity" to="1" dur="0.5s" begin="mouseout" fill="freeze"&gt;&lt;/animate&gt;
          &lt;/rect&gt;
  </code></pre>
  
  <p>To this:</p>
  
  <pre><code>        &lt;rect x="-1.32" y="-0.63" width="3.64" height="1.26" fill="#FFD9D9" stroke-width="0.0" rx="0.12"&gt;
              &lt;!--no animation --&gt;
  
          &lt;/rect&gt;
  </code></pre>
  
  <p>Then we lose animate(hover) effects and speed became ok, like it was in old version FF(37.0.2) with(with not removed) animate tags.</p>
  
  <p>I created topic: <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=1171966" rel="nofollow">https://bugzilla.mozilla.org/show_bug.cgi?id=1171966</a></p>
  
  <p>There were added some examples of code and video to them. The problem of slowness is observed in case of a large number of elements on the page, but only if each of them has the attribute like 'animate'. Maybe alse like this:</p>
  
  <pre><code>        &lt;rect x="-0.5" y="-0.5" width="1" height="1" fill="white"&gt;
              &lt;!--it makes half-visible selecting effect --&gt;
              &lt;set attributeName="stroke-opacity" begin="mouseover" end="mouseout" to="0.5"&gt;&lt;/set&gt;
              &lt;!-- explicitly reverse the opacity animation on mouseout --&gt;
              &lt;set attributeName="stroke-opacity" begin="mouseout" end="mouseover" to="1"&gt;&lt;/set&gt;
          &lt;/rect&gt;
  </code></pre>
  
  <p>In my case, I use  tag to make hover effect and change opacity on mouseover. Not using css, html5, DOM</p>
  
  <p>It would be nice to find similar topics (stackoverflow, bugzilla) or someone who faced this problems too.
  Thanks</p>