//= require modernizr // Method of allowing calculated values for length units, i.e. width: calc(100%-3em) caniuse.com/#search=calc // By @calvein
Modernizr.addTest('csscalc', function() {
var prop = 'width:'; var value = 'calc(10px);'; var el = document.createElement('div'); el.style.cssText = prop + Modernizr._prefixes.join(value + prop); return !!el.style.length;
});