new api: speed

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dplayer",
-  "version": "1.17.5",
+  "version": "1.18.0",
   "description": "Wow, such a lovely HTML5 danmaku video player",
   "main": "dist/DPlayer.min.js",
   "style": "dist/DPlayer.min.css",

src/js/player.js

@@ -478,6 +478,10 @@ class DPlayer {
         this.events.trigger('resize');
     }
 
+    speed (rate) {
+        this.video.playbackRate = rate;
+    }
+
     destroy () {
         instances.splice(instances.indexOf(this), 1);
         this.pause();

src/js/setting.js

@@ -69,7 +69,7 @@ class Setting {
         });
         for (let i = 0; i < this.player.template.speedItem.length; i++) {
             this.player.template.speedItem[i].addEventListener('click', () => {
-                this.player.video.playbackRate = this.player.template.speedItem[i].dataset.speed;
+                this.player.speed(this.player.template.speedItem[i].dataset.speed);
                 this.hide();
             });
         }