Function setClass

06.Router/basic/js/vue.js:1313–1320

* In IE9, setAttribute('class') will result in empty class * if the element also has the :class attribute; However in * PhantomJS, setting `className` does not work on SVG elements... * So we have to do a conditional check here. * * @param {Element} el * @param {String} cls

(el, cls)

   */

  function setClass(el, cls) {
    /* istanbul ignore if */
    if (isIE9 && !/svg$/.test(el.namespaceURI)) {
      el.className = cls;
    } else {
      el.setAttribute('class', cls);
    }
  }

  /**
   * Add class with compatibility for IE & SVG