fix focusing of svg element with tabIndex (#6311)

* fix svg element focusing on `tab` (closes #6262)

* skip IE11

* use nativeMethods

src/client/core/utils/dom.js

@@ -246,7 +246,7 @@ function getInvisibleElements (elements) {
 }
 
 function getTabIndexAttributeIntValue (el) {
-    let tabIndex = el.getAttribute('tabIndex');
+    let tabIndex = nativeMethods.getAttribute.call(el, 'tabindex');
 
     if (tabIndex !== null) {
         tabIndex = parseInt(tabIndex, 10);

test/client/fixtures/automation/press-test.js

@@ -159,6 +159,48 @@ $(document).ready(function () {
             });
     });
 
+    if (!browserUtils.isIE11) {
+        asyncTest('press tab to focus svg', function () {
+            const div = document.createElement('div');
+
+            div.innerHTML = '<button id="btn_prev_svg" tabindex="100">button 1</button>' +
+                            '<svg id="svg_target" tabindex="101"><text x="0" y="15" fill="red">svg</text></svg>' +
+                            '<button id="btn_after_svg" tabindex="102">button 2</button>';
+
+            const btn1 = div.querySelector('#btn_prev_svg');
+            const svg  = div.querySelector('#svg_target');
+            const btn2 = div.querySelector('#btn_after_svg');
+
+            document.body.appendChild(div);
+
+            btn1.focus();
+            ok(btn1 === document.activeElement, document.activeElement.id + ' is focused');
+
+            let press = new PressAutomation(parseKeySequence('tab').combinations, {});
+
+            press
+                .run()
+                .then(function () {
+                    ok(svg === document.activeElement, document.activeElement.id + ' is focused');
+
+                    btn2.focus();
+                    ok(btn2 === document.activeElement, document.activeElement.id + ' is focused');
+
+                    press = new PressAutomation(parseKeySequence('shift+tab').combinations, {});
+
+                    return press
+                        .run();
+                })
+                .then(function () {
+                    ok(svg === document.activeElement, document.activeElement.id + ' is focused');
+
+                    document.body.removeChild(div);
+
+                    start();
+                });
+        });
+    }
+
     module('regression tests');
 
     asyncTest('T334620, GH-3282 - Wrong "key" property in keyEvent objects (press)', function () {