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What is the color of a blank page?

Bastien Calou on May 22, 2020

Please picture the following HTML page in your head: <html> <body> <h1>Hello World</h1> </body> </html&...
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Raphael Schweikert • Edited

I remember in the ’90s when most browsers’ background color was grey. IE was the only one that has a white browser background by default. Others followed suit.

In fact you can change the browser background color in Firefox in about:config by setting browser.display.background_color. I have set this to grey to check if I haven’t accidentally forgotten to add background:white to a page that should have a white background.

I remember when they wanted to fix the weird special-casing of the body tag (which is NOT the root element but can upwards-„inherit“ its color to the html element, which is root) in XHTML. Still today, pages sent with the correct XHTML mime type (application/xhtml+xml) will not show this behaviour. Setting a background on the body tag there won’t make it magically stretch to the canvas.
Sadly, true XHTML never saw any real adoption…

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Bastien Calou

That is super-interesting, thank you so much for this comment.
Would you be ok with me writing a small bonus article and quoting your comment ?
I think more people need to know about this grey background tip.
Very interesting details about xhtml too, thanks!

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Raphael Schweikert

Sure, by all means, bonus away…

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Reece Daniels

xhtml... wow, haven't seen a mention of that in a while

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rhymes

Netscape definitely had a grey "blank page":

netscape navigator

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Bastien Calou

Indeed, I'm currently writing about this! (not the main subject, but part of it)

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manish srivastava

It's a small Hello World after all..... nice article

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Victor Janin

Great Article!
so if we leave our html/body without any background, and the browser changes to dark mode, would that change the browser background?

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Bastien Calou

Thanks!
The answer seems compicated.
I just tried the #enable-force-dark flag to force dark mode on every site on Chrome.
It looks like it doesn't try to replace black background with white : it considers white to be black ! (see screenshot)
So background-color: white | transparent | black | none has the same effect : you see black. I think that yes, the browser's background changes, but that's really a wild guess.
Maybe something to explore in another article ;)

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Bastien Calou

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Taylor Beeston

This was a really well-written article! I think we should petition Google and Mozilla to let us customize our default browser backgrounds. I personally would love it to actually be transparent and show me my desktop through the browser window

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Bastien Calou

I learned that this is possible in Electron by setting the background color of the body to "transparent" !
But nothing like that in the browser indeed

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Victor Magarlamov

Thank you! It's a very interesting article!

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i9

You're a genius writer with your dev stuff, this made me wonder, are a member of the w3c or you sat down and figured this shit out yourself? You're great man. You've added greatly to my knowledge today

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Bastien Calou

Thank you very much, I'm so glad you liked it!
I'm just a front-end teacher ;) One of my student struggled with this mix-blend-mode thing, so I sat down and tried to get to the bottom of this with many tests. Had to read a lot of w3c documentation ^^
Actually I started writing another post on the same subject, because there is too much to say!

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Šime Vidas

The background of the root element becomes the background of the canvas and its background painting area extends to cover the entire canvas.

Human translation: you put a background on the body. The browser will use that as a background for the canvas.

Small correction: The “root element” is the <html> element, not the <body> element.

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Bastien Calou • Edited

Small shortcut, I agree. The <html> is of course the root, but the browser uses the <body> rules as if they were set on the <html>.

"The used values of that BODY element’s background properties are their initial values, and the propagated values are treated as if they were specified on the root element."

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Pacharapol Withayasakpunt • Edited

Iframe has allowtransparency -- stackoverflow.com/questions/374070... so I always know it is transparent.

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Bastien Calou

Thanks, I didn't know about that !
But I could not produce an example in which allowtransparency had any impact. The iframe is transparent by default.
Is it for specific browsers/environments ?

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Claudine

Those wonderful thing we can learn about CSS 😍 thank you for sharing!

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Nicholas Stimpson

Good stuff. Most of this I knew, but the point about the blend-modes had passed me by. Thanks for the explanation.

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leob

Man, this is deep! Good stuff.

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Bayu Angora • Edited

Some website use <canvas> on its view-source, especially when it use particle.js background.

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Ryan Palo

These examples are really, really good.

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Mário Abreu

Interesting article! 👏

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Lance Anderson

I think this is a great article...solves a lot of mysteries

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Ho Honsing

Great post and salute to your adventurous spirit!

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Alexey Vorobyov

Brilliant presentation of such a tricky material!

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Itachi Uchiha

Amazing!

Thanks for this great post.

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Sibusiso Dlamini

I had a good laugh at this 😄😂 . Thanks for that! Keep up the good stuff

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Peyton McGinnis

Creative article! A common misconception many of us neglect. Well written!

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rhymes • Edited

This post is AMAZING! Thanks Bastien, I learned so much :-D

Human translation : there is something behind the canvas.

AHHAHAHA

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myleftshoe

Funny, all the way down to the bottom

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Russell

Thanks. I suspect this has something to do with toggling a dom node into full screen or off screen without a bg color.