Go Back With Backspace extension

go-back-with-backspace/is_editable.js

+// Determine whether focus is in an editable text field.
+function isEditable(path) {
+  var target = path[0];
+
+  // Elements may be explicitly marked as editable.
+  if (target.isContentEditable)
+    return true;
+
+  // Several types of input fields are editable, but not all (e.g., checkboxes).
+  var nodeName = target.nodeName;
+  var nodeType = target.type;
+  if (nodeName === 'TEXTAREA' ||
+      (nodeName === 'INPUT' && (nodeType === 'text' ||
+                                nodeType === 'email' ||
+                                nodeType === 'password' ||
+                                nodeType === 'search'))) {
+    return true;
+  }
+
+  // Certain CSS styles, on elements or their parents, also indicate editable
+  // fields.
+  var pathLength = path.length;
+  for (var i = 0; i < pathLength; ++i) {
+    target = path[i];
+    if (target.nodeType == 1) { // Only Elements have computed styles.
+      var userModify = getComputedStyle(path[i])['-webkit-user-select'];
+      if (userModify == 'read-write' || userModify == 'write-only')
+        return true;
+    }
+  }
+  return false;
+}