docs: update readme

readme.md

@@ -1,7 +1,21 @@
-# animation
+# Animation
 
-A lightweight JavaScript animation library.
-You could use like this [demo](https://holyzfy.github.io/animation/demo.html).
+A lightweight JavaScript animation library. You could use like this [demo](https://holyzfy.github.io/animation/demo.html).
+
+## Demo
+
+```js
+animation.parallel('#elem-1', 'div.elem-2', document.querySelector('.elem-3'))
+    .then(function () {
+        return animation.series(document.querySelectorAll('.demo-xxx'));
+    })
+    .then(function () {
+        return animation.race('#demo-4', '#demo-5');
+    })
+    .then(function () {
+        alert('done');
+    });
+```
 
 ## API
 
@@ -24,7 +38,7 @@ Returns a promise that resolves as soon as one of the animations of the `targets
 
 #### Parameters
 
-The `targets` property defines the elements to animate. 
+The `targets` property defines the elements to animate, you can use the flowing types:
 
 - CSS Selectors
 - DOM Element