(css →  object | array, el → dom)
- add and remove style of element
function (css, el) {
  var style = el.style
  if (isObject(css)) {
    var key
    for (key in css) {
      if (isDefine(style[cssjs(key)])) style[cssjs(key)] = css[key]
    }
  }
  if (isArray(css)) {
    var size = css.length
    var i
    for (i = 0; i < size; i++){
      if (isDefine(style[cssjs(css[i])])) style[cssjs(css[i])] = ""
    }
  }
}