3

No. The browser will send the same information on a refresh as if the user had just come to that page, with the same referrer information. Hence the problem of double-POSTing if someone refreshes the destination page for a form. What you could do is have a refresh button on the page (as Google Ads used to have before they removed it), which you could use to ...


2

Google does not use cache headers to determine how long a page should be in its search index. Googlebot doesn't need to re-crawl the page every time its cached version expires to keep the page in the search index. I'm not sure what is causing your ranking problems, but it is very unlikely to be related to your cache headers. Your cache headers look fine ...


2

if ($_SERVER['HTTP_CACHE_CONTROL'] == 'no-cache') { Also bear in mind that the Cache-Control HTTP request header (as with most request headers) are entirely optional, so may not be present as part of the request at all. (This line would then generate an E_NOTICE under these conditions.) In fact, I don't believe Googlebot sends the Cache-Control header when ...


2

It is always better to have proper 404 responses. However, search engines can deal with both JS redirects to 404 pages and blank pages. They should treat them the same as a proper 404 error. There is a long history of web servers redirecting to error pages rather than showing a proper error status directly. Search engine bots have to be programmed to ...


2

Browsers do send additional headers, but behavior different. This info in link a bit outdated: stackoverflow question Looks like Cache-control:no-cache is the best solution, to check for Ctrl+F5, but better to check not the only one header. Just checked on Firefox Ubuntu, F5 gives nothing, but Ctrl+F5 request contain this Pragma no-cache Cache-Control ...


1

If I understand your question, you're asking how the web server knows which domain to send the request to. You are correct about host headers. HTTP(S) 1.1 added host headers as a way for web servers to host more than one host/domain. When you make a request via your web browser, it sends a request via HTTP(S). The protocol includes both the IP ...


1

The content-type is used by browsers to figure out how to display the content. Browsers have to choose the rendering method based on the content type. Rendering plain text is very different than rendering HTML. wget performs the same action for all files: it saves them to disk. In my experience it doesn't pay attention to the Content-Type header, it ...


1

You may not be explicitly setting HTTP headers but wget certainly will be. If you run the same command with the -d (debug) flag you'll see more verbose output including the request and response headers: $ wget -d https://webmasters.stackexchange.com/robots.txt [...] ---request begin--- GET /robots.txt HTTP/1.1 User-Agent: Wget/1.20.1 (linux-gnu) Accept: */*...


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