ajax请求序列化问题 about frontend-interview HOT 5 OPEN

    buttonA.onclick = function(){
      get('/a', function(resTxt){
        console.log(resTxt)
        input.value = resTxt
      })
    }

    buttonB.onclick = function(){
      get('/b', function(resTxt){
        console.log(resTxt)
        input.value = resTxt
      })
    }


    function get(url, callback){
      
      if(!Array.isArray(get.xhrQueue)){
        get.xhrQueue = []
      }
      var xhrQueue = get.xhrQueue
      var xhr  = new XMLHttpRequest()
      xhrQueue.push(xhr)
      xhr.opts = {}
      xhr.onloadend = function(){
        this.opts.finished = true
        checkQueue()
      }

      xhr.opts.finished = false
      xhr.opts.callback = callback
      xhr.timeout = 1000*8
      xhr.open('get', url, true)
      xhr.send()
      
      function checkQueue(){
        var xhr = xhrQueue[0]
        while(xhr && xhr.opts.finished){
          if(xhr.status == 200 || xhr.status == 304){
            xhr.opts.callback(xhr.responseText)
          }
          xhrQueue.shift()
          xhr = xhrQueue[0]
        }

      }
    }