Question

我需要AJAX加载大二进制文件，因此我想显示一个进度指示器。我已经读过当设置了“Content-Length”标头时，Progress.event参数的lengthComputable字段为true。我有这个标题，但lengthComputable总是false。我做错了什么？。

以下是代码：

function onProgress(evt){
    if(evt.lengthComputable){
        this.progress = (evt.loaded / evt.total)*100; 
        // do something  ...
    }
}

function load(url){
    var me = this;
    var xhr = new XMLHttpRequest();
    xhr.open('GET', url, true);
    xhr.responseType = 'arraybuffer';   
    xhr.onload = this.load;
    xhr.onprogress = this.updateProgress;
    xhr.send();
}

这是标题（来自Chrome）：

Request URL:http://localhost/cgi-bin/test.cgi
Request Method:GET
Status Code:200 OK
Request Headersview source
Accept:*/*
Accept-Encoding:gzip,deflate,sdch
Accept-Language:es-419,es;q=0.8
Connection:keep-alive
Cookie:__utma=1.1581312881.1342448904.1342729430.1342812228.5
Host:localhost
Referer:http://localhost/cgi-bin/test.cgi
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.35 (KHTML, like Gecko) Chrome/27.0.1448.0 Safari/537.35
Query String Parametersview sourceview URL encoded
idimage:3431
Response Headersview source
Connection:Keep-Alive
Content-Encoding:deflate
Content-Length:11825252
Content-Type:application/binaryfile
Date:Fri, 05 Apr 2013 11:36:06 GMT
Keep-Alive:timeout=5, max=98
Server:Apache/2.2.22 (FreeBSD) mod_ssl/2.2.22 OpenSSL/0.9.8x DAV/2 PHP/5.3.10 with Suhosin-Patch mod_python/3.3.1 Python/2.7.3 mod_perl/2.0.5 Perl/v5.10.1

编辑：看起来问题是Content-Encoding，在我的情况下是deflate：How can I use deflated/gzipped content with an XHR onProgress function?

XMLHttpRequest lengthComputable总是为false

0 个答案: