function cssAddClass(el, className) {
  const classNames = split(className);
  for (let i = 0; i < classNames.length; i++) {
    if (!cssHasClass(el, classNames[i])) {
      el.className = `${el.className} ${classNames[i]}`;
    }
  }

  return el.className;
}
/**
 * Adds the given class name to the given element
 *
 * @param {Element} el        The element
 * @param {String}  className One or more space separated class names
 * @returns {String}
 */
Adds the given class name to the given element
@param {Element} el        The element
@param {String}  className One or more space separated class names
@returns {String}
Adds the given class name to the given element @param { Element } el The element @param { String } className One or more space separated class names @returns { String }
function cssAddClass(el, className) {
  const classNames = split(className);
  for (let i = 0; i < classNames.length; i++) {
    if (!cssHasClass(el, classNames[i])) {
      el.className = `${el.className} ${classNames[i]}`;
    }
  }
  return el.className;
}
function cssAddClass ( el , className ) { const classNames = split ( className ) ; for ( let i = 0 ; i < classNames . length ; i ++ ) { if ( ! cssHasClass ( el , classNames [ i ] ) ) { el . className = ` ${ el . className } ${ classNames [ i ] } ` ; } } return el . className ; }
Adds the given class name to the given element
 @param {Element} el        The element
 @param {String}  className One or more space separated class names
 @returns {String}
Adds the given class name to the given element @param { Element } el The element @param { String } className One or more space separated class names @returns { String }