Add support for shadow DOM and fix event target bug

README.md

@@ -5,6 +5,12 @@ Focus movement by arrow keys
 
 It allows you to focus elements with arrow keys inside a container.  
 
+- Works inside shadow dom.
+- Use focusgroup="wrap" to focus the first element when the last element is focused and vice versa.
+- Use focusgroup="remember" to focus the last focused element when group is focused again.
+- Text-Inputs only works for up and down arrow keys.
+
+
 See also:  
 https://open-ui.org/components/focusgroup.explainer/  
 https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/Focusgroup/explainer.md

focusgroup.js

@@ -72,7 +72,8 @@ function eventTargets(event){
 	let target = event.target;
 	let container = target.closest('[u1-focusgroup]');
 	if (!container) { // inside shadow dom
-		target = event.originalTarget;
+		target = event.originalTarget; // only for firefox?
+		if (!target) return {};
 		container = target.closest('[u1-focusgroup]');
 	}
 	// TODO? handle slotted elements