--- a/testing/marionette/element.js
+++ b/testing/marionette/element.js
@@ -29,25 +29,16 @@ this.EXPORTED_SYMBOLS = [
 
 const {
   FIRST_ORDERED_NODE_TYPE,
   ORDERED_NODE_ITERATOR_TYPE,
 } = Ci.nsIDOMXPathResult;
 const ELEMENT_NODE = 1;
 const DOCUMENT_NODE = 9;
 
-const UNEDITABLE_INPUTS = new Set([
-  "checkbox",
-  "radio",
-  "hidden",
-  "submit",
-  "button",
-  "image",
-]);
-
 const XBLNS = "http://www.mozilla.org/xbl";
 const XULNS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 /** XUL elements that support checked property. */
 const XUL_CHECKED_ELS = new Set([
   "button",
   "checkbox",
   "listitem",
@@ -839,16 +830,70 @@ element.isDisabled = function(el) {
       return el.disabled;
 
     default:
       return false;
   }
 };
 
 /**
+ * Denotes elements that can be used for typing and clearing.
+ *
+ * Elements that are considered WebDriver-editable are non-readonly
+ * and non-disabled <code>&lt;input&gt;</code> elements in the Text,
+ * Search, URL, Telephone, Email, Password, Date, Month, Date and
+ * Time Local, Number, Range, Color, and File Upload states, and
+ * <code>&lt;textarea&gt;</code> elements.
+ *
+ * @param {Element} el
+ *     Element to test.
+ *
+ * @return {boolean}
+ *     True if editable, false otherwise.
+ */
+element.isMutableFormControl = function(el) {
+  if (!element.isDOMElement(el)) {
+    return false;
+  }
+  if (element.isReadOnly(el) || element.isDisabled(el)) {
+    return false;
+  }
+
+  if (el.localName == "textarea") {
+    return true;
+  }
+
+  if (el.localName != "input") {
+    return false;
+  }
+
+  switch (el.type) {
+    case "color":
+    case "date":
+    case "datetime-local":
+    case "email":
+    case "file":
+    case "month":
+    case "number":
+    case "password":
+    case "range":
+    case "search":
+    case "tel":
+    case "text":
+    case "time":
+    case "url":
+    case "week":
+      return true;
+
+    default:
+      return false;
+  }
+};
+
+/**
  * An editing host is a node that is either an HTML element with a
  * <code>contenteditable</code> attribute, or the HTML element child
  * of a document whose <code>designMode</code> is enabled.
  *
  * @param {Element} el
  *     Element to determine if is an editing host.
  *
  * @return {boolean}
@@ -887,19 +932,17 @@ element.isEditable = function(el) {
   if (!element.isDOMElement(el)) {
     return false;
   }
 
   if (element.isReadOnly(el) || element.isDisabled(el)) {
     return false;
   }
 
-  return (el.localName == "input" && !UNEDITABLE_INPUTS.has(el.type)) ||
-      el.localName == "textarea" ||
-      element.isEditingHost(el);
+  return element.isMutableFormControl(el) || element.isEditingHost(el);
 };
 
 /**
  * This function generates a pair of coordinates relative to the viewport
  * given a target element and coordinates relative to that element's
  * top-left corner.
  *
  * @param {Node} node

--- a/testing/marionette/test_element.js
+++ b/testing/marionette/test_element.js
@@ -39,20 +39,25 @@ class Element {
     return tags.includes(this.localName);
   }
 }
 
 class DOMElement extends Element {
   constructor(tagName, attrs = {}) {
     super(tagName, attrs);
 
-    this.namespaceURI = XHTMLNS;
+    if (typeof this.namespaceURI == "undefined") {
+      this.namespaceURI = XHTMLNS;
+    }
     if (typeof this.ownerDocument == "undefined") {
       this.ownerDocument = {designMode: "off"};
     }
+    if (typeof this.type == "undefined") {
+      this.type = "text";
+    }
 
     if (this.localName == "option") {
       this.selected = false;
     }
 
     if (this.localName == "input" && ["checkbox", "radio"].includes(this.type)) {
       this.checked = false;
     }
@@ -253,16 +258,50 @@ add_test(function test_isEditable() {
 
   ok(element.isEditable(new DOMElement("textarea")));
   ok(element.isEditable(new DOMElement("p", {ownerDocument: {designMode: "on"}})));
   ok(element.isEditable(new DOMElement("p", {isContentEditable: true})));
 
   run_next_test();
 });
 
+add_test(function test_isMutableFormControlElement() {
+  ok(!element.isMutableFormControl(null));
+  ok(!element.isMutableFormControl(new DOMElement("textarea", {readOnly: true})));
+  ok(!element.isMutableFormControl(new DOMElement("textarea", {disabled: true})));
+
+  const mutableStates = new Set([
+    "color",
+    "date",
+    "datetime-local",
+    "email",
+    "file",
+    "month",
+    "number",
+    "password",
+    "range",
+    "search",
+    "tel",
+    "text",
+    "url",
+    "week",
+  ]);
+  for (let type of mutableStates) {
+    ok(element.isMutableFormControl(new DOMElement("input", {type})));
+  }
+  ok(element.isMutableFormControl(new DOMElement("textarea")));
+
+  ok(!element.isMutableFormControl(new DOMElement("input", {type: "hidden"})));
+  ok(!element.isMutableFormControl(new DOMElement("p")));
+  ok(!element.isMutableFormControl(new DOMElement("p", {isContentEditable: true})));
+  ok(!element.isMutableFormControl(new DOMElement("p", {ownerDocument: {designMode: "on"}})));
+
+  run_next_test();
+});
+
 add_test(function test_coordinates() {
   let p = element.coordinates(domEl);
   ok(p.hasOwnProperty("x"));
   ok(p.hasOwnProperty("y"));
   equal("number", typeof p.x);
   equal("number", typeof p.y);
 
   deepEqual({x: 50, y: 50}, element.coordinates(domEl));