vUnit is a vanilla JS microlib (~1000 bytes after gzip) that allows you to size elements based on the viewport dimensions, without relying on the buggy vh/vw/vmin/vmax CSS units. See a live example.
4x4 panel, 50% height and width:
First: install using bower or npm:
bower install vunit or npm install vunit.js
Second: add the script to the <head> tag and instantiate vUnit passing a CSSMap object:
<head>
<!-- Add vUnit.js to the head to avoid FOUC -->
<script src="path/to/vunit.js"></script>
<!-- Instantiate vUnit.js passing a CSSMap with properties you want to play with -->
<script>
new vUnit({
CSSMap: {
// The selector (VUnit will create rules ranging from .selector1 to .selector100)
'.vh_height': {
// The CSS property (any CSS property that accepts px as units)
property: 'height',
// What to base the value on (vh, vw, vmin or vmax)
reference: 'vh'
},
// Wanted to have a font-size based on the viewport width? You got it.
'.vw_font-size': {
property: 'font-size',
reference: 'vw'
},
// vmin and vmax can be used as well.
'.vmin_margin-top': {
property: 'margin-top',
reference: 'vmin'
}
},
onResize: function() {
console.log('A screen resize just happened, yo.');
}
}).init(); // call the public init() method
</script>
</head>
<body>
<h1 class="vw_font-size15">This title font-size is 15% of the viewport width.</h1>
<p class="vh_height50">This p's height is 50% of the viewport height.</p>
<p class="vmin_margin-top5">This p has some margin-top<p>
</body>Third: Add the generated classes to your HTML elements:
<h1 class="vw_font-size15">This title font-size is 15% of the viewport width.</h1>
<p class="vh_height50">This p's height is 50% of the viewport height.</p>
<p class="vmin_margin-top5">This p has some margin-top.<p>You're done!
Viewport relative units are awesome, except they're not - they are buggy, unreliable and have inconsistent implementation across browsers. vUnit.js offers a lightweight, robust alternative for them and weighs ~600 bytes after gzip.
vUnit.js calculates the browser viewport dimensions and creates CSS rules ranging from 1% to 100% of its size. These rules are then inserted into a stylesheet which is injected on the fly to the <head> tag.
An observer running every 100ms checks if the viewport has been resized and regenerates the CSS rules accordingly. It's a cross-device, event-less solution to keep track of everything that would trigger a resize on the viewport, namely:
- Window resizing on desktop;
- Orientation change on mobile;
- Scrollbars appearing/disappearing on desktop;
- Navigation bars appearing/disappearing on mobile;
- Zooming on mobile and desktop;
- Download bar on desktop;
- Password saving prompt on desktop;
- Etc.
- Load vUnit on the
<head>tag to avoid FOUC. - Add a CSS transition on mobile, so it doesn't jitter as the address bar appears/disappears.
- vUnit is pretty fast, but avoid bloating your CSSMap with properties you won't gonna use.
- vUnit is not supposed to replace your grid, but to enhance your design.
- Always consider non-JS users.
So far, tested on:
- IE8+
- Chrome
- Firefox
- Safari
- Chrome for Android
- Android Browser 4.3
More to come.
- The issues page is your friend.