access participants' browser info

[aliona]

Dear Jeremy,
I was wondering whether there’s a possibility for me to see which browser participants used for my experiment. Apparently, there’s a problem of loading the resources (images) from Imgur and I wanted to see whether that can be browser specific as I know that e.g., on Safari the position of the images in my experiment gets all messed up.

Thank you in advance,
Aliona

[Jeremy]

Dear Aliona,

Each submission in the results file starts with these lines:

# Results on Friday February 26 2021 14:31:11 UTC
# USER AGENT: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:85.0) Gecko/20100101 Firefox/85.0

As you can see, in this case, the submission came from a participant (me) who used Firefox. This is not 100% reliable, but there is no method that is 100% reliable when it comes to determining the browser’s identity

Jeremy

[aliona]

Dear Jeremy,

thanks for getting back to me!
I was hoping I could use those lines too, but in some cases several browsers are listed and I wasn’t sure how to interpret that.

`USER AGENT: Mozilla/xx (xxxxxxxxx) xxxxxx (xxxxxxxx) Chrome/xxxxxxx Safari/xxxxxxx Edg/xxxxxxx

I guess this is then the case of the info not being 100% reliable.

Best,
Aliona

[Jeremy]

Dear Aliona,

The line you report most likely corresponds to Edge (although you should probably see an extra ‘e’ at “Edg/xxxxxxx”): http://useragentstring.com/index.php?id=19970

Jeremy

[aliona]

Oh, I see! Thanks a lot for the link!

Best,
Aliona

[elena-vsg]

Hi Jeremy,

I have a somewhat related question: my experiment does not render properly in Safari and I would like to exclude participants using Safari from my study. Is there a way to implement a browser test?

Thank you!

[Jeremy]

Hi,

Yes, you can do something like this for example:

Sequence("block", "intro", randomize("experiment"))

if (navigator.vendor.match(/apple/i))
    newTrial( "block" ,
        newText("<p>We're sorry, but this experiment is not compatible with your browser.</p>").print()
        ,
        newText("<p>We encourage you to revisit this experiment \
                    using a desktop or laptop version of Chrome or Firefox if possible.</p>").print()
        ,
        newText("<p>Thank you for your understanding.</p>").print()
        ,
        newButton().wait()
    )

Note that filtering participants after recruiting them is against some recruitment platforms’ policy, such as Prolific’s (last time I checked)

Jeremy

[Author]

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