diff --git a/mithril.js b/mithril.js
index 8a2d1166..155e6909 100644
--- a/mithril.js
+++ b/mithril.js
@@ -235,7 +235,7 @@ Mithril = m = new function app(window, undefined) {
 				cached = {
 					tag: data.tag,
 					//set attributes first, then create children
-					attrs: dataAttrKeys.length ? setAttributes(node, data.tag, data.attrs, {}, namespace) : {},
+					attrs: hasKeys ? setAttributes(node, data.tag, data.attrs, {}, namespace) : {},
 					children: data.children != null && data.children.length > 0 ?
 						build(node, data.tag, undefined, undefined, data.children, cached.children, true, 0, data.attrs.contenteditable ? node : editable, namespace, configs) :
 						data.children,
@@ -248,7 +248,7 @@ Mithril = m = new function app(window, undefined) {
 			}
 			else {
 				node = cached.nodes[0];
-				if (dataAttrKeys.length) setAttributes(node, data.tag, data.attrs, cached.attrs, namespace);
+				if (hasKeys) setAttributes(node, data.tag, data.attrs, cached.attrs, namespace);
 				cached.children = build(node, data.tag, undefined, undefined, data.children, cached.children, false, 0, data.attrs.contenteditable ? node : editable, namespace, configs);
 				cached.nodes.intact = true;
 				if (shouldReattach === true && node != null) parentElement.insertBefore(node, parentElement.childNodes[index] || null)
@@ -318,8 +318,7 @@ Mithril = m = new function app(window, undefined) {
 				cachedAttrs[attrName] = dataAttr;
 				try {
 					//`config` isn't a real attributes, so ignore it
-					//we don't ignore `key` because it must be unique and having it on the DOM helps debugging
-					if (attrName === "config") continue;
+					if (attrName === "config" || attrName == "key") continue;
 					//hook event handlers to the auto-redrawing system
 					else if (typeof dataAttr == sFn && attrName.indexOf("on") == 0) {
 						node[attrName] = autoredraw(dataAttr, node)
diff --git a/tests/mithril-tests.js b/tests/mithril-tests.js
index 6b3212d5..de9f97be 100644
--- a/tests/mithril-tests.js
+++ b/tests/mithril-tests.js
@@ -509,55 +509,55 @@ function testMithril(mock) {
 		//https://github.com/lhorie/mithril.js/issues/98
 		//insert at beginning
 		var root = mock.document.createElement("div")
-		m.render(root, [m("a", {key: 1}), m("a", {key: 2}), m("a", {key: 3})])
+		m.render(root, [m("a", {key: 1}, 1), m("a", {key: 2}, 2), m("a", {key: 3}, 3)])
 		var firstBefore = root.childNodes[0]
-		m.render(root, [m("a", {key: 4}), m("a", {key: 1}), m("a", {key: 2}), m("a", {key: 3})])
+		m.render(root, [m("a", {key: 4}, 4), m("a", {key: 1}, 1), m("a", {key: 2}, 2), m("a", {key: 3}, 3)])
 		var firstAfter = root.childNodes[1]
-		return firstBefore == firstAfter && root.childNodes[0].key == 4 && root.childNodes.length == 4
+		return firstBefore == firstAfter && root.childNodes[0].childNodes[0].nodeValue == "4" && root.childNodes.length == 4
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/98
 		var root = mock.document.createElement("div")
-		m.render(root, [m("a", {key: 1}), m("a", {key: 2}), m("a", {key: 3})])
+		m.render(root, [m("a", {key: 1}, 1), m("a", {key: 2}, 2), m("a", {key: 3}, 3)])
 		var firstBefore = root.childNodes[0]
-		m.render(root, [m("a", {key: 4}), m("a", {key: 1}), m("a", {key: 2})])
+		m.render(root, [m("a", {key: 4}, 4), m("a", {key: 1}, 1), m("a", {key: 2}, 2)])
 		var firstAfter = root.childNodes[1]
-		return firstBefore == firstAfter && root.childNodes[0].key == 4 && root.childNodes.length == 3
+		return firstBefore == firstAfter && root.childNodes[0].childNodes[0].nodeValue == 4 && root.childNodes.length == 3
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/98
 		var root = mock.document.createElement("div")
-		m.render(root, [m("a", {key: 1}), m("a", {key: 2}), m("a", {key: 3})])
+		m.render(root, [m("a", {key: 1}, 1), m("a", {key: 2}, 2), m("a", {key: 3}, 3)])
 		var firstBefore = root.childNodes[1]
-		m.render(root, [m("a", {key: 2}), m("a", {key: 3}), m("a", {key: 4})])
+		m.render(root, [m("a", {key: 2}, 2), m("a", {key: 3}, 3), m("a", {key: 4}, 4)])
 		var firstAfter = root.childNodes[0]
-		return firstBefore == firstAfter && root.childNodes[0].key === "2" && root.childNodes.length === 3
+		return firstBefore == firstAfter && root.childNodes[0].childNodes[0].nodeValue === "2" && root.childNodes.length === 3
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/98
 		var root = mock.document.createElement("div")
-		m.render(root, [m("a", {key: 1}), m("a", {key: 2}), m("a", {key: 3}), m("a", {key: 4}), m("a", {key: 5})])
+		m.render(root, [m("a", {key: 1}, 1), m("a", {key: 2}, 2), m("a", {key: 3}, 3), m("a", {key: 4}, 4), m("a", {key: 5}, 5)])
 		var firstBefore = root.childNodes[0]
 		var secondBefore = root.childNodes[1]
 		var fourthBefore = root.childNodes[3]
-		m.render(root, [m("a", {key: 4}), m("a", {key: 10}), m("a", {key: 1}), m("a", {key: 2})])
+		m.render(root, [m("a", {key: 4}, 4), m("a", {key: 10}, 10), m("a", {key: 1}, 1), m("a", {key: 2}, 2)])
 		var firstAfter = root.childNodes[2]
 		var secondAfter = root.childNodes[3]
 		var fourthAfter = root.childNodes[0]
-		return firstBefore === firstAfter && secondBefore === secondAfter && fourthBefore === fourthAfter && root.childNodes[1].key == "10" && root.childNodes.length === 4
+		return firstBefore === firstAfter && secondBefore === secondAfter && fourthBefore === fourthAfter && root.childNodes[1].childNodes[0].nodeValue == "10" && root.childNodes.length === 4
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/98
 		var root = mock.document.createElement("div")
-		m.render(root, [m("a", {key: 1}), m("a", {key: 2}), m("a", {key: 3}), m("a", {key: 4}), m("a", {key: 5})])
+		m.render(root, [m("a", {key: 1}, 1), m("a", {key: 2}, 2), m("a", {key: 3}, 3), m("a", {key: 4}, 4), m("a", {key: 5}, 5)])
 		var firstBefore = root.childNodes[0]
 		var secondBefore = root.childNodes[1]
 		var fourthBefore = root.childNodes[3]
-		m.render(root, [m("a", {key: 4}), m("a", {key: 10}), m("a", {key: 2}), m("a", {key: 1}), m("a", {key: 6}), m("a", {key: 7})])
+		m.render(root, [m("a", {key: 4}, 4), m("a", {key: 10}, 10), m("a", {key: 2}, 2), m("a", {key: 1}, 1), m("a", {key: 6}, 6), m("a", {key: 7}, 7)])
 		var firstAfter = root.childNodes[3]
 		var secondAfter = root.childNodes[2]
 		var fourthAfter = root.childNodes[0]
-		return firstBefore === firstAfter && secondBefore === secondAfter && fourthBefore === fourthAfter && root.childNodes[1].key == "10" && root.childNodes[4].key == "6" && root.childNodes[5].key == "7" && root.childNodes.length === 6
+		return firstBefore === firstAfter && secondBefore === secondAfter && fourthBefore === fourthAfter && root.childNodes[1].childNodes[0].nodeValue == "10" && root.childNodes[4].childNodes[0].nodeValue == "6" && root.childNodes[5].childNodes[0].nodeValue == "7" && root.childNodes.length === 6
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/149
@@ -580,11 +580,11 @@ function testMithril(mock) {
 		//https://github.com/lhorie/mithril.js/issues/246
 		//insert at beginning with non-keyed in the middle
 		var root = mock.document.createElement("div")
-		m.render(root, [m("a", {key: 1})])
+		m.render(root, [m("a", {key: 1}, 1)])
 		var firstBefore = root.childNodes[0]
-		m.render(root, [m("a", {key: 2}), m("br"), m("a", {key: 1})])
+		m.render(root, [m("a", {key: 2}, 2), m("br"), m("a", {key: 1}, 1)])
 		var firstAfter = root.childNodes[2]
-		return firstBefore == firstAfter && root.childNodes[0].key == 2 && root.childNodes.length == 3
+		return firstBefore == firstAfter && root.childNodes[0].childNodes[0].nodeValue == 2 && root.childNodes.length == 3
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/134
@@ -687,9 +687,9 @@ function testMithril(mock) {
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/157
 		var root = mock.document.createElement("div")
-		m.render(root, m("ul", [m("li", {key: 0}), m("li", {key: 2}), m("li", {key: 4})]))
-		m.render(root, m("ul", [m("li", {key: 0}), m("li", {key: 1}), m("li", {key: 2}), m("li", {key: 3}), m("li", {key: 4}), m("li", {key: 5})]))
-		return root.childNodes[0].childNodes.map(function(n) {return n.key}).join("") == "012345"
+		m.render(root, m("ul", [m("li", {key: 0}, 0), m("li", {key: 2}, 2), m("li", {key: 4}, 4)]))
+		m.render(root, m("ul", [m("li", {key: 0}, 0), m("li", {key: 1}, 1), m("li", {key: 2}, 2), m("li", {key: 3}, 3), m("li", {key: 4}, 4), m("li", {key: 5}, 5)]))
+		return root.childNodes[0].childNodes.map(function(n) {return n.childNodes[0].nodeValue}).join("") == "012345"
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/157
@@ -708,17 +708,17 @@ function testMithril(mock) {
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/194
 		var root = mock.document.createElement("div")
-		m.render(root, m("ul", [m("li", {key: 0}), m("li", {key: 1}), m("li", {key: 2}), m("li", {key: 3}), m("li", {key: 4}), m("li", {key: 5})]))
-		m.render(root, m("ul", [m("li", {key: 0}), m("li", {key: 1}), m("li", {key: 2}), m("li", {key: 4}), m("li", {key: 5})]))
-		return root.childNodes[0].childNodes.map(function(n) {return n.key}).join("") == "01245"
+		m.render(root, m("ul", [m("li", {key: 0}, 0), m("li", {key: 1}, 1), m("li", {key: 2}, 2), m("li", {key: 3}, 3), m("li", {key: 4}, 4), m("li", {key: 5}, 5)]))
+		m.render(root, m("ul", [m("li", {key: 0}, 0), m("li", {key: 1}, 1), m("li", {key: 2}, 2), m("li", {key: 4}, 4), m("li", {key: 5}, 5)]))
+		return root.childNodes[0].childNodes.map(function(n) {return n.childNodes[0].nodeValue}).join("") == "01245"
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/194
 		var root = mock.document.createElement("div")
-		m.render(root, m("ul", [m("li", {key: 0}), m("li", {key: 1}), m("li", {key: 2}), m("li", {key: 3}), m("li", {key: 4}), m("li", {key: 5})]))
-		m.render(root, m("ul", [m("li", {key: 1}), m("li", {key: 2}), m("li", {key: 3}), m("li", {key: 4}), m("li", {key: 5}), m("li", {key: 6})]))
-		m.render(root, m("ul", [m("li", {key: 12}), m("li", {key: 13}), m("li", {key: 14}), m("li", {key: 15}), m("li", {key: 16}), m("li", {key: 17})]))
-		return root.childNodes[0].childNodes.map(function(n) {return n.key}).join(",") == "12,13,14,15,16,17"
+		m.render(root, m("ul", [m("li", {key: 0}, 0), m("li", {key: 1}, 1), m("li", {key: 2}, 2), m("li", {key: 3}, 3), m("li", {key: 4}, 4), m("li", {key: 5}, 5)]))
+		m.render(root, m("ul", [m("li", {key: 1}, 1), m("li", {key: 2}, 2), m("li", {key: 3}, 3), m("li", {key: 4}, 4), m("li", {key: 5}, 5), m("li", {key: 6}, 6)]))
+		m.render(root, m("ul", [m("li", {key: 12}, 12), m("li", {key: 13}, 13), m("li", {key: 14}, 14), m("li", {key: 15}, 15), m("li", {key: 16}, 16), m("li", {key: 17}, 17)]))
+		return root.childNodes[0].childNodes.map(function(n) {return n.childNodes[0].nodeValue}).join(",") == "12,13,14,15,16,17"
 	})
 	test(function() {
 		//https://github.com/lhorie/mithril.js/issues/206