res

CSS resolution detection in JavaScript

npm install res --save

API

res.dpi()

• Get resolution in dpi
• @return number

res.dpcm()

• Get resolution in dpcm
• @return number

res.dppx()

• Get resolution in dppx
• @return number

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.

Related resources

• actual
• CSS4 resolution
• CSS3 resolution and units
• Demo media queries
• Resolution lab

License

MIT