Question

xml.setRequestHeader('If-Modified-Since', '0'); 在HttpWebRequest 里面怎么设置

抓包得到的数据：

GET /ajax/GetCount.aspx?id=0&nows=1367742955902 HTTP/1.1
Accept: */*
Accept-Language: zh-cn
Referer: http://127.0.0.1/index.aspx
If-Modified-Since: 0
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)
Host: 127.0.0.1
Connection: Keep-Alive
Cookie: ASP.NET_SessionId=kzcfqaa3kilah2ejlrkisf45; username=; questionId=

Answer 1

HttpWebRequest.Headers.Add("If-Modified-Since", "0");

追答

如果是0的话，应该可以不用添加此 header