Function toggleClass

js/plugins/sortable.js:251–260

(el, name, state)

  var R_SPACE = /\s+/g;

  function toggleClass(el, name, state) {
    if (el && name) {
      if (el.classList) {
        el.classList[state ? 'add' : 'remove'](name);
      } else {
        var className = (' ' + el.className + ' ').replace(R_SPACE, ' ').replace(' ' + name + ' ', ' ');
        el.className = (className + (state ? ' ' + name : '')).replace(R_SPACE, ' ');
      }
    }
  }

  function css(el, prop, val) {
    var style = el && el.style;