From 5524075b04e28548e71254ae01205a58d02ecaac Mon Sep 17 00:00:00 2001
From: Theo Arends <11044339+arendst@users.noreply.github.com>
Date: Sat, 30 Nov 2019 16:05:09 +0100
Subject: [PATCH] Fix slider for devices without RGB

Fix slider for devices with one or two channels like only white or white/yellow
---
 tasmota/CHANGELOG.md          | 2 ++
 tasmota/xdrv_01_webserver.ino | 8 +++++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/tasmota/CHANGELOG.md b/tasmota/CHANGELOG.md
index 2810f33736b9..235471a07e24 100644
--- a/tasmota/CHANGELOG.md
+++ b/tasmota/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ### 7.1.0.1 20191130
 
+- Fix slider for devices with one or two channels like only white or white/yellow
+
 ## Released
 
 ### 7.1.0 20191129
diff --git a/tasmota/xdrv_01_webserver.ino b/tasmota/xdrv_01_webserver.ino
index 42630b8baa53..48e2cd26af76 100644
--- a/tasmota/xdrv_01_webserver.ino
+++ b/tasmota/xdrv_01_webserver.ino
@@ -154,9 +154,11 @@ const char HTTP_SCRIPT_ROOT[] PROGMEM =
 
 const char HTTP_SCRIPT_ROOT_PART2[] PROGMEM =
   "function lc(v,i,p){"
-    "if(v=='h'||v=='d'){"                 // Hue or Brightness changed so change Saturation colors too
-      "var sl=eb('sl4').value;"
-      "eb('s').style.background='linear-gradient(to right,rgb('+sl+'%%,'+sl+'%%,'+sl+'%%),hsl('+eb('sl2').value+',100%%,50%%))';"
+    "if(eb('s')){"                        // Check if Saturation is in DOM otherwise javascript fails on la()
+      "if(v=='h'||v=='d'){"               // Hue or Brightness changed so change Saturation colors too
+        "var sl=eb('sl4').value;"
+        "eb('s').style.background='linear-gradient(to right,rgb('+sl+'%%,'+sl+'%%,'+sl+'%%),hsl('+eb('sl2').value+',100%%,50%%))';"
+      "}"
     "}"
     "la('&'+v+i+'='+p);"
   "}"