title: What's the difference between "onwheel" and "onscroll" events?
body: <p>When I tried to change the default scroll bar property, I found that it's not convenient by rewriting callback function for <code>scroll()</code> or <code>onscroll</code> events, instead, I should rewrite a callback function for "onwheel" events.</p>
  
  <p>So what's the difference between <code>onwheel</code> and <code>onscroll</code> anyways? I imagine that default <code>onwheel</code> handler by browsers would automatically trigger <code>onscroll</code> function to move the scroll bar, which is why <code>preventDefault</code> in <code>onwheel</code>'s callback will prevent scroll bar moving. Am I right? Who has a better and more specific explanation?</p>