Use coercion to be smart about value assignment

Author: nhunzaker

src/renderers/dom/client/wrappers/ReactDOMInput.js

@@ -199,14 +199,11 @@ var ReactDOMInput = {
     var node = ReactDOMComponentTree.getNodeFromInstance(inst);
     var value = LinkedValueUtils.getValue(props);
     if (value != null) {
-
-      // Cast `value` to a string to ensure the value is set correctly. While
-      // browsers typically do this as necessary, jsdom doesn't.
-      var newValue = '' + value;
-
       // To avoid side effects (such as losing text selection), only set value if changed
-      if (newValue !== node.value) {
-        node.value = newValue;
+      if (value != node.value) {
+        // Cast `value` to a string to ensure the value is set correctly. While
+        // browsers typically do this as necessary, jsdom doesn't.
+        node.value = '' + value;
       }
     } else {
       if (props.value == null && props.defaultValue != null) {

src/renderers/dom/shared/DOMPropertyOperations.js

@@ -158,8 +158,8 @@ var DOMPropertyOperations = {
         } else if (propertyInfo.hasBooleanValue ||
                    (propertyInfo.hasOverloadedBooleanValue && value === true)) {
           node.setAttribute(attributeName, '');
-        } else if (attributeName === 'value') {
-          if (node.value !== value) {
+        } else if (attributeName === 'value' && node.hasAttribute('value')) {
+          if (node.value != value) {
             node.setAttribute(attributeName, '' + value);
           }
         } else {