javascript-ajax文件下载：进度事件,用于下载

我了解xhr.upload.onprogress事件(文件上传).
像这样 ：

    xhr.upload.onprogress = function(e) {   // if (e.lengthComputable) ...
        var percentUploaded = Math.floor(100 * e.loaded / e.total);
        progressBarElem.value = percentUploaded;
        messageAreaElem.innerHTML = percentUploaded + "% uploaded";
    }

但是xhr.onprogress事件(从服务器下载文件)呢？

我找不到一个简单的例子.

帕特里克

解决方法:

如Document所说：

Progress events exist for both download and upload transfers. The download events are fired on the XMLHttpRequest object itself, as shown in the above sample. The upload events are fired on the XMLHttpRequest.upload object.

您可以尝试使用以下代码进行验证

var progress = 0.1;

var oReq = new XMLHttpRequest();

//Download progress
oReq.addEventListener("progress", function(evt){
  if (evt.lengthComputable) {
    var percentComplete = evt.loaded / evt.total;
    //Do something with download progress
    console.log(evt.total);
    if(percentComplete > progress ){
        console.log("Finish " + progress * 100 + "%.");
        progress += 0.1;

    }
  }
}, false);

oReq.open("get", "url", true);
oReq.send();