JM

Jet Movement detects scrollUp and scrollDown movement for you.

Introduction

// when you scroll the page up it excutes the function `fn`
jm.scrollUp(fn)

// when you scroll the page down it excutes the function `fn`
jm.scrollDown(fn)

A real-world example

Auto hiding website's Navbar when scroll down and show when scroll up, see it alive.

HTML:

<header class="header">
  <h1>Jet Movement</h1>
</header>

CSS:

.header {
  height: 50px;
  background-color: #fff;
  border-bottom: 1px solid #e2e2e2;
  line-height: 50px;
  text-align: center;
  transform: translateY(0);
  transition: transform .3s ease;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
}
.hidden-header {
  transform: translateY(-100%);
}

JavaScript:

const header = document.querySelector('.header')
jm.navbarHeight = header.clientHeight

jm.scrollDown(() => {
  header.classList.add('hidden-header')
})

jm.scrollUp(() => {
  header.classList.remove('hidden-header')
})

Inspired by Hide header on scroll down, show on scroll up.

License

MIT.