[Site] Fix mobile tabindex

source/nodejs/adaptivecards-site/themes/adaptivecards/layout/sample.ejs

@@ -52,7 +52,7 @@
 				<div class="w3-cell-row2">
 					<div class="w3-cell" style="width: 50px;">
 						<label>
-							<input type="checkbox" checked id="enableTemplating" class="bigbox" />
+							<input type="checkbox" checked id="enableTemplating" class="bigbox" tabIndex="0" />
 						</label>
 					</div>
 					<div class="w3-cell w3-cell-middle">

source/nodejs/adaptivecards-site/themes/adaptivecards/source/js/script.js

@@ -595,6 +595,20 @@ $(function () {
 		// Kick off one resize to fix all videos on page load
 	}).resize();
 
+    function makeTabIndicesZero() {
+        $("[tabindex]").each((i, elem) => {
+            if (elem.tabIndex > 0) {
+                elem.setAttribute("tabindex", 0);
+            }
+        });
+    }
+
+    // rewrite non-zero tabindex values (UHF script can add explicit tabindices, breaking keyboard tab order)
+    $(window).resize(makeTabIndicesZero);
+
+    // this is sadly fragile, but should work in the majority of cases (I'm so sorry).
+    $(document).ready(() => { setTimeout(makeTabIndicesZero, 200); });
+
 	// Code for making sidebar sticky
 	var headerHolder;
 	var footerHolder;