function check(elm, rule) {
  let input = elm.getElementsByTagName('input')[0]
  rules[rule.validator](input, rule.trigger, (s, error) => {
    if (s) {
      elm.className = 'input-box'
      let eElm = elm.getElementsByClassName('input-error-text')[0]
      if(eElm) {
        elm.removeChild(eElm)
      }
    }
    else {
      elm.className = 'input-box error'
      let e = rule.message || error
      let eElm = document.createElement('span');
      eElm.className = 'input-error-text'
      eElm.innerHTML = e
      elm.appendChild(eElm)
    }
  })
}

const rules = {
  notEmpty: (input, trigger, cd) => {
    input.addEventListener(trigger, ()=>{
      if (input.value) {
        cd(true)
      }
      else {
        cd(false, '不能为空！')
      }
    })
  }
}

export { check }