我有一个angular 4应用程序，在Chrome中运行良好，但是IE和FF显示400错误的请求，当我比较IE和Chrome之间的http标头时，我看到IE，FF添加了其他标头。当我在Firefox中删除“ If-Modified-Since：0”标头并重新发送（通过FF开发人员工具）时，它返回200 OK。可能是这里的问题，以及为什么IE / Firefox失败而不是chrome失败了，这似乎是由于这些缓存头所致。
这是IE标头
GET {domain path}/assets/environments/environment.json HTTP/1.1
Referer: {host}/index.html
X-HttpWatch-RID: 45248-10892
Cache-Control: no-cache
Pragma: no-cache
If-Modified-Since: 0
Accept: application/json, text/plain, */*
Accept-Language: en-US
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko
Host: {host domain}
DNT: 1
Connection: Keep-Alive
Cookie: _ga=GA1.2.1512081247.1492526215; _rollup=GA1.2.973698029.1530531199; ASP.NET_SessionId=jj12nlqxiugx24xj33m34anf;
这里是Chrome标头（比IE少的数字）
GET {domain path}/assets/environments/environment.json HTTP/1.1
Host: {host domain}
Connection: keep-alive
Accept: application/json, text/plain, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36
Referer: {host}/index.html
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Cookie: {value}