diff --git a/fhem/FHEM/01_FHEMWEB.pm b/fhem/FHEM/01_FHEMWEB.pm
index b9b41eba0..76d531660 100755
--- a/fhem/FHEM/01_FHEMWEB.pm
+++ b/fhem/FHEM/01_FHEMWEB.pm
@@ -1088,6 +1088,7 @@ FW_showRoom()
               my $cv = ReadingsVal($d, $cmd, Value($d));
               $cmd = "" if($cmd eq "state");
               $cv =~ s/.*?(\d+).*/$1/; # get first number
+              $cv = 0 if($cv !~ m/\d/);
               FW_pO "<td colspan='2'>".
                       "<div class='slider' id='slider.$d' ".
                            "min='$min' stp='$stp' max='$max' ".
diff --git a/fhem/www/pgm2/fhemweb.js b/fhem/www/pgm2/fhemweb.js
index 38d987a67..5e62520fa 100644
--- a/fhem/www/pgm2/fhemweb.js
+++ b/fhem/www/pgm2/fhemweb.js
@@ -60,6 +60,8 @@ FW_doUpdate()
       }
       if(doSet) {
         var val = d[1].replace(/^.*?(\d+).*/g, "$1"); // get first number
+        if(!val.match(/\d+/))
+          val = 0;
         Slider(el, val);
       }
     }