code: function buildStyleCache() {
  	styleCache = {
  		width: {},
  		height: {},
  	};
  	var rules;
  	for (var i = 0; i < styleSheets.length; i++) {
  		if (styleSheets[i].disabled) {
  			continue;
  		}
  		try {
  			rules = styleSheets[i].cssRules;
  			if (!rules || !rules.length) {
  				continue;
  			}
  		}
  		catch(e) {
  			continue;
  		}
  		buildStyleCacheFromRules(rules);
  	}
  }
docs: Builds the styleCache needed by getOriginalStyle