Added support for a container to scroll in

README.md

@@ -86,7 +86,8 @@ Jump.jump('.selector', {
     if(t < 1) return c / 2 * t * t + b
     t--
     return -c / 2 * (t * (t - 2) - 1) + b
-  }
+  },
+  container: '.selector'
 })
 ```
 
@@ -144,6 +145,16 @@ Jump.jump('.selector', {
 })
 ```
 
+##### container
+
+Container when you want to `jump()` inside an element.
+
+```es6
+Jump.jump('.selector', {
+  container: '.selector'
+})
+```
+
 ## Browser Support
 
 Jump depends on the following browser APIs:

src/jump.js

@@ -8,7 +8,8 @@ export default class Jump {
       duration: options.duration,
       offset: options.offset || 0,
       callback: options.callback,
-      easing: options.easing || easeInOutQuad
+      easing: options.easing || easeInOutQuad,
+      container: document.querySelector(options.container) || null
     }
 
     this.distance = typeof target === 'string'
@@ -30,15 +31,20 @@ export default class Jump {
     this.timeElapsed = time - this.timeStart
     this.next = this.options.easing(this.timeElapsed, this.start, this.distance, this.duration)
 
-    window.scrollTo(0, this.next)
+    !!this.options.container
+      ? this.options.container.scrollTop = this.next
+      : window.scrollTo(0, this.next)
 
     this.timeElapsed < this.duration
       ? requestAnimationFrame(time => this._loop(time))
       : this._end()
   }
 
   _end() {
-    window.scrollTo(0, this.start + this.distance)
+
+    !!this.options.container
+      ? this.options.container.scrollTop = this.next + this.distance
+      : window.scrollTo(0, this.next + this.distance)
 
     typeof this.options.callback === 'function' && this.options.callback()
     this.timeStart = false