XmlHtt prequest onprogress区间 [英] XmlHttpRequest onprogress interval

问题描述

我用XmlHtt prequests将图像上传到服务器，我想向用户展示这些上传的进度。

I'm using XmlHttpRequests to upload images to a server and I'd like to show the user the progress of these uploads.

不幸的是打到我onprogress事件处理程序之间的间隔过大。通常onprogress被称为只有一次或两次为500K的形象。

Unfortunately the interval between calls to my onprogress-event handler is too large. Usually onprogress is called only once or twice for a 500k image.

下面是我的code：

/* This function is not called often enough */
function progress(e){
    console.log('Uploading: ' + Math.round((e.loaded / e.total) * 100) + ' %');
}

var xhr = new XMLHttpRequest();
xhr.upload.addEventListener('progress', progress, false);
xhr.send(data);

可这种行为被改变，或者这是很难codeD某处在浏览器中执行？

Can this behaviour be changed or is this hardcoded somewhere in the browser implementation?

推荐答案

在W3阐述在他们的 XMLHtt prequest 2级文件。显然，不同的一致性程度不同的浏览器是可以预期的。

The W3 sets forth the following guidelines in their XMLHttpRequest Level 2 document. Obviously varying levels of conformance across browsers are to be expected.

上传：

而请求实体正文正在上传，并上传完成标志是假的，排队一个任务触发一个名为约每50ms或每一个字节XMLHtt prequestUpload对象进度传输进度事件，取其是最常见的。 - W3 XMLHtt prequest 2级（加粗为重点）

While the request entity body is being uploaded and the upload complete flag is false, queue a task to fire a progress event named progress at the XMLHttpRequestUpload object about every 50ms or for every byte transmitted, whichever is least frequent. - W3 XMLHttpRequest Level 2 (Bolded for emphasis)

下载：

当有人说取得进展的通知，而下载的进展，排队任务解雇约每隔50ms或收到的每个字节，取其最频繁 progress事件命名的进步。 - W3 XMLHtt prequest 2级（加粗为重点）

When it is said to make progress notifications, while the download is progressing, queue a task to fire a progress event named progress about every 50ms or for every byte received, whichever is least frequent. - W3 XMLHttpRequest Level 2 (Bolded for emphasis)

我不知道一个API来定义这个功能。

I am not aware of an api to customize this functionality.

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