text: /*exported injectStyle */
  /*global axe*/
  
  var styleSheet;
  function injectStyle(style) {
  	'use strict';
  
  	if (styleSheet && styleSheet.parentNode) {
  		// append the style to the existing sheet
  		if (styleSheet.styleSheet === undefined) {
  			// Not old IE
  			styleSheet.appendChild(document.createTextNode(style));
  		} else {
  			styleSheet.styleSheet.cssText += style;
  		}
  		return styleSheet;
  	}
  	if (!style) {
  		return;
  	}
  
  	var head = document.head || document.getElementsByTagName('head')[0];
  	styleSheet = document.createElement('style');
  	styleSheet.type = 'text/css';
  
  	if (styleSheet.styleSheet === undefined) {
  		// Not old IE
  		styleSheet.appendChild(document.createTextNode(style));
  	} else {
  		styleSheet.styleSheet.cssText = style;
  	}
  
  	head.appendChild(styleSheet);
  
  	return styleSheet;
  }
  
  axe.utils.injectStyle = injectStyle;
  