code: function (el, classid) {
    createEl.exit = el
    var cElm_enter = createEl.$enter.length
  
    // remove element if has in createEl.$enter
    var i
    if (cElm_enter > 0) {
      for (i = 0;i < cElm_enter; i++) {
        if (isDefine(createEl.$enter[i]) && isDefine(createEl.$enter[i].class) && createEl.$enter[i].class === classid) {
          createEl.$enter.splice(i,1)
        }
      }
    }
  
    // push an element
    if (!hasObj_Array(createEl.$exits, 'class', classid).is) createEl.$exits.push({class: classid, el: el})
  }
docs: (el → dom, classid → string)
  - add element has exit