code: function style(el, obj) {
  		if ( !obj ) {
  			return window.getComputedStyle(el);
  		}
  		if ("[object Object]" === Object.prototype.toString.call(obj)) {
  			var s = "";
  			each(obj, function(prop, val) {
  
  				if ( typeof val !== "string" && prop !== "opacity" ) {
  					val += "px";
  				}
  
  				s += prop + ": " + val + ";";
  			});
  			el.style.cssText += s;
  		}
  	}
docs: Emulate jQuery's css method
  @param  {Object} el   HTMLElement
  @param  {Object} prop CSS properties and values
  @return {Object|Void}