diff --git a/src/dom/dom.js b/src/dom/dom.js
index 5bd1781f..c9340d44 100644
--- a/src/dom/dom.js
+++ b/src/dom/dom.js
@@ -11,6 +11,10 @@ class dom {
 	 * @param {string} classes CSS classes to add.
 	 */
 	static addClasses(element, classes) {
+		if (!core.isObject(element) || !core.isString(classes)) {
+			return;
+		}
+
 		if ('classList' in element) {
 			dom.addClassesWithNative_(element, classes);
 		} else {
@@ -297,6 +301,10 @@ class dom {
 	 * @param {string} classes CSS classes to remove.
 	 */
 	static removeClasses(element, classes) {
+		if (!core.isObject(element) || !core.isString(classes)) {
+			return;
+		}
+
 		if ('classList' in element) {
 			dom.removeClassesWithNative_(element, classes);
 		} else {
diff --git a/test/src/dom/dom.js b/test/src/dom/dom.js
index a5ad3426..a6cdb6d6 100644
--- a/test/src/dom/dom.js
+++ b/test/src/dom/dom.js
@@ -51,6 +51,16 @@ describe('dom', function() {
 			dom.removeClassesWithoutNative_(element, 'class2');
 			assert.ok(!dom.hasClass(element, 'class2'));
 		});
+
+		it('should do nothing if element or classes are not object and string', function() {
+			var element = document.createElement('div');
+			dom.addClasses(element);
+			assert.strictEqual(element.className, '');
+
+			dom.addClasses(element, 'class1');
+			dom.removeClasses(element);
+			assert.isTrue(dom.hasClass(element, 'class1'));
+		});
 	});
 
 	describe('manipulation', function() {