function getsec(time) {
      return time / 1000 + ‘s‘
}
window.onload = function () {
      var per = window.performance.timing;
      console.log(‘DNS查询耗时‘ + getsec(per.domainLookupEnd - per.domainLookupStart))
      console.log(‘TCP链接耗时‘ + getsec(per.connectEnd - per.connectStart))
      console.log(‘request请求响应耗时‘ + getsec(per.responseEnd - per.responseStart))
      console.log(‘dom渲染耗时‘ + getsec(per.domComplete - per.domInteractive))
     //  console.log(‘白屏时间‘ + getsec(firstPaint - pageStartTime))
      console.log(‘domready可操作时间‘ + getsec(per.domContentLoadedEventEnd - per.fetchStart))
    }