CODEWITHSUNDEEP
javascriptbrowsersearch-enginehtml
Tennyson H
Tennyson H

Reputation: 1716

How do websites know they're not the default home page or search provider?

As far as I'm aware, there is no public API exposure of a browser's default homepage/search provider. So how does Google know to display this? It only comes around when Google's not the default homepage / default search provider on my browser.

Google on-page popup: 'Get to Google faster. Switch your default search engine to Google.' Googe on-page popup: 'Come here often? Make Google your homepage.'

I can only assume they're inferring from numerous variables, such as the referrer. I wasn't able to successfully dig down into Google's compiled JavaScript. I'm not even sure if it's detected client-side or server-side.

I'm on Firefox 44, but I've seen these banners on Chrome, too.

Upvotes: 89

Views: 6330

Answers (3)

Shailendra Sharma
Shailendra Sharma

Reputation: 6992

Simply there is no way to do that with JavaScript because the "default search/homepage" is a user's preference and you do not have access to that without user's permission because that would be a security/privacy issue.

What Google does at every user visit is show a promo ad with a close icon and a go button with instructions on how to set it as the default homepage. On click of any one of them, it creates 2 cookies so that next time it will check your cookies and make the promos disappear. Even when Google is your homepage and you clear your cookies then a banner is still there to promote Google as your homepage.

I have checked this with Firefox, not aware of Chrome.

Upvotes: 70

Piskvor left the building
Piskvor left the building

Reputation: 92772

I don't know what Google does, exactly, but what I would do:

  • set the homepage URL with some special parameter and check it - 'http://www.example.com/#!homepage (prevents false negatives)
  • check for Referer field:
    • if it's NOT there, assume user has typed it in manually
    • if it's very similar for each user visit (and perhaps at what looks like the beginning of a browsing session - inferred via GA on eeevery page out there), assume user is coming here by always clicking through from somewhere
  • set a cookie, e.g. visitedHelpAboutHomePage when the user visits the "yes, show me" page (might prevent false negatives, but might also generate false positives)

Note that the "special parameter" does happen in the "searchbox-initiated search" scenario: there is a parameter sourceid which likely means "source of search."

Upvotes: 19

cutmancometh
cutmancometh

Reputation: 1737

In my Firefox (v42), the "Come here often?" box appears even when I have Google set as the default search provider.

In Safari I get a box in the same location that says "A better way to browse the web: Get Google Chrome"

In Opera and Chrome I get no box at all, even if I change my default search provider to something other than Google.

So, I believe all they're doing is browser detection in the JavaScript, using the UserAgent object.

Upvotes: 11

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