Replace hexToRgb function to work with legacy mobile browsers

pyleds/templates/index.html

@@ -7,11 +7,15 @@
     <link rel="stylesheet" href="custom.css">
 
     <script type="text/javascript">
-        const hexToRgb = hex =>
-            hex.replace(/^#?([a-f\d])([a-f\d])([a-f\d])$/i
-                ,(m, r, g, b) => '#' + r + r + g + g + b + b)
-                .substring(1).match(/.{2}/g)
-                .map(x => parseInt(x, 16));
+        function hexToRgb(value) {
+            var aRgbHex = value.substring(1).match(/.{1,2}/g);
+            var aRgb = [
+                parseInt(aRgbHex[0], 16),
+                parseInt(aRgbHex[1], 16),
+                parseInt(aRgbHex[2], 16)
+            ];
+            return aRgb;
+        }
 
         function show_loading(visible) {
             document.getElementById('loading').style.visibility = visible ? 'visible' : 'hidden';