(el → dom, classid → string)
- add element has enter
function (el, classid) {
  createEl.enter = el
  var cElm_exits = createEl.$exits.length

  // remove element if has in createEl.$exits
  var i
  if (cElm_exits > 0) {
    for (i = 0;i < cElm_exits; i++) {
      // make sure that element is exits
      if (isDefine(createEl.$exits[i]) && isDefine(createEl.$exits[i].class) && createEl.$exits[i].class === classid) {
        createEl.$exits.splice(i,1)
      }
    }
  }

  // push an element
  if (!hasObj_Array(createEl.$enter, 'class', classid).is) createEl.$enter.push({class: classid, el: el})
}