code: function(duration){
  		if(duration===0) throw new Error('Duration must not be === 0');
  		if(!S.isString(duration)) return duration;
  		return duration.contains('ms') ? parseInt(duration, 10) : parseInt(duration, 10) * 1000; 
  	}
docs: Common functions /*
  var insertRule=(function(){
  if( document.styleSheets && document.styleSheets.length ) {
  var styleSheet=document.styleSheets[0];
  return function(keyframes){ styleSheet.insertRule( keyframes, 0 ); }
  }else{
  var s = document.createElement( 'style' );
  document.head.appendChild( s );
  return function(keyframes){ s.innerHTML = s.innerHTML + keyframes };
  }
  })();