text: //     Zepto.js
  //     (c) 2010-2016 Thomas Fuchs
  //     Zepto.js may be freely distributed under the MIT license.
  
  ;(function(){
    // getComputedStyle shouldn't freak out when called
    // without a valid element as argument
    // 有些浏览器getComputedStyle()第一个参数不是正常的element时,会报错, 如果有这种情况return null,防止报错
    try {
      getComputedStyle(undefined)
    } catch(e) {
      var nativeGetComputedStyle = getComputedStyle
      window.getComputedStyle = function(element, pseudoElement){
        try {
          return nativeGetComputedStyle(element, pseudoElement)
        } catch(e) {
          return null
        }
      }
    }
  })()
  