title: Range Slider: jQuery changes value but slider do not move
body: <p>I run the following program:</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
      &lt;meta charset="UTF-8"&gt;
      &lt;title&gt; Slider &lt;/title&gt;
      &lt;!-- jQuery CDN https://code.jquery.com/ --&gt;
      &lt;script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"&gt;&lt;/script&gt; 
      &lt;script type="text/javascript"src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"&gt;&lt;/script&gt;
      &lt;script&gt;
      $(document).ready(function() {
          console.debug("jQuery "+ (jQuery ? $().jquery : "NOT") +" loaded"); // jQuery version to console
          $('#slider1').slider({value: "11"});                                // initialize slider
          $("#slider1").slider("option", "value", 2);       
          $("#slider1" ).slider("value", 3 );
          var value = $( "#slider1" ).slider( "option", "value");    // show slider value 
          $('#sliderVal').text("Slider Value: "+value);
  
          $('#slider1').on('input', function(event) {                     // show slider value when changed
              var valSlider1 =  $(this).attr('id') +"   Value:" +$(this).val();
              $('#sliderVal').text(valSlider1);
          });
      });
      &lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;p&gt; Slider &lt;/p&gt; 
      &lt;input type="range" class="sl" id="slider1"  min="0" max="100" value="99"&gt;  
      &lt;p id="sliderVal"&gt;...&lt;/p                     //display value of slider
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>After running the programm the slider's "thumb" still stands on 99
  The output (id=sliderVal; second last line) says:  Slider Value: 3<br>
  I tried</p>
  
  <pre><code> $('#slider1').slider({value: "11"});       
   $("#slider1").slider("option", "value", 2);       
   $("#slider1" ).slider("value", 3 );
  </code></pre>
  
  <p>They all change the slider's value, but the slider thumb never moves.
  When I move the slider's thumb with the mouse  the correct values are displayed</p>