verge

verge is a compact set of cross-browser viewport utilities written in native JavaScript. It includes the ability to detect if an element is in the current viewport. It works as a standalone module, an ender module, or as a jQuery plugin. (npm: verge)

API

.viewportW()
.viewportH()
.viewport() 1.8+
.inViewport()
.inX()
.inY()
.scrollX()
.scrollY()
.mq() 1.6+
.rectangle()
.aspect() 1.7+

Accuracy

verge's viewport methods represent the CSS viewport and thus match @media (width) and @media (height) breakpoints.
At certain zooms the viewport dimensions given by verge may be 1px off the expected @media value due to native rounding. For greater precision (at a slight speed tradeoff) consider actual.

.viewportW()

verge.viewportW() // -> viewport width in pixels

.viewportH()

verge.viewportH() // -> viewport height in pixels

.viewport()

Get both CSS viewport dimensions as an object with width and height properties.

verge.viewportW() === verge.viewport().width  // always true 
verge.viewportH() === verge.viewport().height // always true

The .viewportW() syntax is slightly faster.

.inViewport()

Test if any part of an element (or the first element in a matched set) is in the current viewport. Returns boolean.

verge.inViewport(elem) // true if elem is in the current viewport 
verge.inViewport(elem, 100) // true if elem is in the current viewport or within 100px of it 
verge.inViewport(elem, -100) // true if elem is in the current viewport and not within 99px of the edge

Performance tip for sites that only scroll along 1 axis

verge.inViewport(elem) === verge.inX(elem) && verge.inY(elem) // always true

Substitute inViewport with: inY on vertical sites, inX on horizontal ones.

On pages without horizontal scroll, inX is always true.
On pages without vertical scroll, inY is always true.
If the viewport width is >= the document width, then inX is always true.

.inX()

Test if any part of an element (or the first element in a matched set) is in the same x-axis section as the viewport. Returns boolean.

verge.inX(elem) // true if elem is in same x-axis as the viewport (exact) 
verge.inX(elem, 100) // true if elem is in same x-axis as the viewport or within 100px of it 
verge.inX(elem, -100) // true if elem in is the viewport and not within 99px of the edge

.inY()

Test if any part of an element (or the first element in a matched set) is in the same y-axis section as the viewport. Returns boolean.

verge.inY(elem) // true if elem is in same y-axis as the viewport (exact) 
verge.inY(elem, 100) // true if elem is in same y-axis as the viewport or within 100px of it 
verge.inY(elem, -100) // true if elem in is the viewport and not within 99px of the edge

.scrollX()

Get the horizontal scroll position in pixels. (Like window.scrollX, but cross-browser.)

verge.scrollX() // -> horizontal pixels scrolled

.scrollY()

Get the vertical scroll position in pixels. (Like window.scrollY, but cross-browser.)

verge.scrollY() // -> vertical pixels scrolled

.mq()

.mq(mediaQueryString)

Test if a media query is active.

verge.mq('(min-color:2)') // -> boolean 
verge.mq('tv') // -> boolean

.rectangle()

.rectangle(element, cushion?)

Get an a object containing the properties top, bottom, left, right, width, and height with respect to the top-left corner of the current viewport, and with an optional cushion amount. Its return is like that of the native getBoundingClientRect.

The optional cushion parameter is an amount of pixels to act as a cushion around the element. If none is provided then it defaults to 0 and the rectangle will match the native rectangle. If a cushion is specified, the properties are adjusted according to the cushion amount. If the cushion is positive the rectangle will represent an area that is larger that the actual element. If the cushion is negative then the rectangle will represent an area that is smaller that the actual element.

verge.rectangle(element) // rectangle object 
verge.rectangle(element, 100) // rectangle object adjusted by 100 pixels

.aspect()

.aspect(object?)

Get the aspect ratio of the viewport or of an object with width/height properties.

verge.aspect() // -> viewport aspect ratio 
verge.aspect(element) // -> element aspect ratio 
verge.aspect(screen) // -> device aspect ratio 
1 < verge.aspect() // => landscape orientation