How to know if web page is returned from another website

Question

I have website link http://example.com/link/

How can I handle if it returns from such as: http://facebook.com

I want to check and process event by something like this:

if(return from facebook) {
}

Jquery or PHP is ok.Thank you for your advice.

Would phps `$_SERVER['HTTP_REFERER'];` do the job? http://php.net/manual/en/reserved.variables.server.php — atoms, Oct 21 '17 at 00:28
[How to know if user came from a Facebook link?](https://stackoverflow.com/q/19485746/1415724) - You should read that. It's going to answer what you're hoping will work; it won't. Same thing here [How reliable is HTTP_REFERER?](https://stackoverflow.com/a/6023980/1415724) — Funk Forty Niner, Oct 21 '17 at 01:04
Thank you, @Fred-ii-. I will read it now.Update: Thank you so much. — Hai Tien, Oct 21 '17 at 01:09

atoms · Accepted Answer · 2017-10-21T00:49:09.333

2

You could find the referer in PHP using:

$_SERVER['HTTP_REFERER']

if($_SERVER['HTTP_REFERER'] == 'https://facebook.com'){ }

However, you'd probably want to catch anything from facebook;

$sReg = '.facebook.+[a-zA-Z](\/*)';

if(preg_match( $sReg, $_SERVER['HTTP_REFERER'] == 1 ){

}

Note that HTTP_REFERER isn't a sure way of getting the referrer. Often it'll be missing.

See PHP manual for more info

edited Oct 21 '17 at 00:49

answered Oct 21 '17 at 00:37

atoms

Thank for your answer but if "HTTP_REFERER isn't a sure way of getting the referrer" then can you use another method for sure? – Hai Tien Oct 21 '17 at 00:41
unfortunately some browsers wont supply it, be it for privacy or other configuration reasons. See https://stackoverflow.com/questions/6023941/how-reliable-is-http-referer – atoms Oct 21 '17 at 00:46
2

No, you can not. Users can decide not to let their browsers to send a referrer, or a fake one. And websites can these days also specify whether they want the browser to send a full referrer, the domain name only, or none at all. – CBroe Oct 21 '17 at 00:47
Thank atoms and Cbroe for your support. I understood. – Hai Tien Oct 21 '17 at 00:49

Yulio Aleman Jimenez · Answer 2 · 2017-10-21T00:46:55.040

1

The solution in javascript

if(document.referrer == 'https://facebook.com') {
    /* Do somethings */
}

Using Regular Expression:

var myRe = new RegExp('facebook.+[a-zA-Z](\/*)');
if(myRe.test(document.referrer)) {
    /* Do somethings */
}

edited Oct 21 '17 at 00:46

answered Oct 21 '17 at 00:41

what if someone disables JS? can you answer that detail? – Funk Forty Niner Oct 21 '17 at 00:49
Thank you for your answer, let me test with this. – Hai Tien Oct 21 '17 at 00:50
@BuiPhuc Accordingly of your environment, you would use both solutions (PHP and JS) to get a better result. – Yulio Aleman Jimenez Oct 21 '17 at 00:55
@YulioAlemanJimenez: Thank you for your advice. Perhaps I have to combine both js and php. – Hai Tien Oct 21 '17 at 01:00

2 Answers2