diff --git a/fhem/FHEM/01_FHEMWEB.pm b/fhem/FHEM/01_FHEMWEB.pm
index 7860c0d02..99986d221 100755
--- a/fhem/FHEM/01_FHEMWEB.pm
+++ b/fhem/FHEM/01_FHEMWEB.pm
@@ -2439,9 +2439,10 @@ FW_sliderFn($$$$$)
 {
   my ($FW_wname, $d, $FW_room, $cmd, $values) = @_;
 
-  return undef if($values !~ m/^slider,(.*),(.*),(.*)$/);
+  return undef if($values !~ m/^slider,([\d.]*),([\d.]*),([\d.]*)(,1)?$/);
   return "" if($cmd =~ m/ /);   # webCmd pct 30 should generate a link
-  my ($min,$stp, $max) = ($1, $2, $3);
+  my ($min,$stp, $max, $flt) = ($1, $2, $3, $4);
+  $flt = ($flt ? 1 : 0);
   my $srf = $FW_room ? "&room=$FW_room" : "";
   my $cv = ReadingsVal($d, $cmd, Value($d));
   my $id = ($cmd eq "state") ? "" : "-$cmd";
@@ -2450,7 +2451,7 @@ FW_sliderFn($$$$$)
   $cv = 0 if($cv !~ m/\d/);
   return "<td colspan='2'>".
            "<div class='slider' id='slider.$d$id' min='$min' stp='$stp' ".
-                 "max='$max' cmd='$FW_ME?cmd=set $d $cmd %$srf'>".
+                 "max='$max' cmd='$FW_ME?cmd=set $d $cmd %$srf' flt='$flt'>".
              "<div class='handle'>$min</div>".
            "</div>".
            "<script type=\"text/javascript\">".
@@ -3085,8 +3086,10 @@ FW_widgetOverride($$)
             displayed.</li>
           <li>if the modifier is ":textField", an input field is displayed.</li>
           <li>if the modifier is of the form
-            ":slider,&lt;min&gt;,&lt;step&gt;,&lt;max&gt;", then a javascript
-            driven slider is displayed</li>
+            ":slider,&lt;min&gt;,&lt;step&gt;,&lt;max&gt;[,1]", then a
+            javascript driven slider is displayed. The optional ,1 at the end
+            avoids the rounding of floating-point numbers.</li>
+
           <li>if the modifier is of the form ":multiple,val1,val2,...", then
             multiple values can be selected and own values can be written, the
             result is comma separated.</li>
@@ -3651,8 +3654,9 @@ FW_widgetOverride($$)
               angezeigt.</li>
 
           <li>Ist der Modifier in der Form
-            ":slider,&lt;min&gt;,&lt;step&gt;,&lt;max&gt;", so wird ein in
-            JavaScript programmierter Slider angezeigt</li>
+            ":slider,&lt;min&gt;,&lt;step&gt;,&lt;max&gt;[,1]", so wird ein in
+            JavaScript programmierter Slider angezeigt. Das optionale 1
+            (isFloat) vermeidet eine Rundung der Fliesskommazahlen </li>
 
           <li>Ist der Modifier ":multiple,val1,val2,...", dann ist eine
             Mehrfachauswahl m&ouml;glich und es k&ouml;nnen neue Werte gesetzt
diff --git a/fhem/www/pgm2/fhemweb_slider.js b/fhem/www/pgm2/fhemweb_slider.js
index 863876c09..98107fc5f 100644
--- a/fhem/www/pgm2/fhemweb_slider.js
+++ b/fhem/www/pgm2/fhemweb_slider.js
@@ -36,6 +36,7 @@ FW_sliderCreate(slider, curr)
   var min = parseFloat(slider.getAttribute("min"));
   var stp = parseFloat(slider.getAttribute("stp"));
   var max = parseFloat(slider.getAttribute("max"));
+  var flt = parseFloat(slider.getAttribute("flt"));
   var cmd = slider.getAttribute("cmd");
 
   function
@@ -78,7 +79,8 @@ FW_sliderCreate(slider, curr)
       if(offX < 0) offX = 0;
       if(offX > maxX) offX = maxX;
       val = min+(offX/maxX * (max-min));
-      val = Math.floor(Math.floor(val/stp)*stp);
+      val = (flt ? Math.floor(val/stp)*stp :
+                   Math.floor(Math.floor(val/stp)*stp));
       sh.innerHTML = val;
       sh.setAttribute('style', 'left:'+offX+'px;');
       if(cmd && cmd.substring(0,3) == "js:") {
@@ -112,17 +114,20 @@ FW_sliderCreate(slider, curr)
 function
 FW_sliderSelChange(name, devName, vArr)
 {
-  if(vArr.length != 4 || vArr[0] != "slider")
+  if(vArr.length < 4 || vArr.length > 5 || vArr[0] != "slider")
     return undefined;
 
   var o = new Object();
   var min=parseFloat(vArr[1]),
       stp=parseFloat(vArr[2]),
-      max=parseFloat(vArr[3]);
+      max=parseFloat(vArr[3]),
+      flt=parseFloat(vArr[4]);
+  if(!flt) flt=0;
   o.newEl = document.createElement('div');
   o.newEl.innerHTML =
-    '<div class="slider" id="slider.'+devName+'" min="'+min+'" stp="'+stp+
-              '" max="'+max+'"><div class="handle">'+min+'</div></div>'+
+    '<div class="slider" id="slider.'+devName+
+        '" min="'+min+'" stp="'+stp+'" max="'+max+'" flt="'+flt+
+        '"><div class="handle">'+min+'</div></div>'+
     '<input type="hidden" name="'+name+'" value="'+min+'">';
   FW_sliderCreate(o.newEl.firstChild, undefined);