res

Device resolution detection module

res

CSS resolution detection in JavaScript

API

`res.dpi()`

@return number resolution in dpi

`res.dpcm()`

@return number resolution in dpcm

`res.dppx()`

@return number resolution in dppx

Usage

var res = require('res')
res.dppx() // 1 
res.dpi() // 96 
res.dpcm() // 37.79527559055118

Technical notes

dppx equals devicePixelRatio
dppx is the preferred resolution unit for web design
User zoom affects resolution

Use with care

res was mainly written for investigative purposes. Making retina design accommodations can be impractical. Consider alternatives to resolution detection.

Example outputs

Device	`res.ddpx()`	`res.dpi()`	`res.dpcm()`
desktop at default zoom	1	96	37.79527559055118
iPhone 4s at default zoom	2	192	75.59055118110236

Compatibility

Browsers with resolution detectable by res

Webkit (Chrome/Safari/Android)
Firefox 18+
Opera 11.1+ (Presto 2.8+)
IE 6+

Methods return 0 where undetectable.

CSS4 resolution
CSS3 resolution and units
Resolution lab
Demo media queries
ryanve/actual

License

MIT

res

res