Merge pull request #923 from ant-design/chore-form

refactor: make code more robust

components/form/FormItem.jsx

@@ -48,7 +48,7 @@ class FormItem extends React.Component {
       return 'validating';
     } else if (!!getFieldError(field)) {
       return 'error';
-    } else if (getFieldValue(field)) {
+    } else if (getFieldValue(field) !== undefined) {
       return 'success';
     }
   }

components/form/demo/validate-customized.md

@@ -75,7 +75,7 @@ let Demo = React.createClass({
     this.getPassStrenth(value, 'pass');
 
     if (form.getFieldValue('pass')) {
-      form.validateFields(['rePass']);
+      form.validateFields(['rePass'], { force: true });
     }
 
     callback();