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Is the appearance of Javascript alerts modifiable in Firefox 4.0?

  • 7 replies
  • 18 have this problem
  • 61 views
  • Last reply by cor-el

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Firefox 4.0 allows users to do a lot of customizing, which is great. Does this extend to the appearance of Javascript alerts?

Unlike Firefox 3.6, in version 4.0 when an alert pops up, the underlying web page is darkened, half opaque and half transparent. This focuses the user's attention on the alert box. Is there a way for me to change this setting to be 20% opaque, 80% transparent? That would make it easier for me to see what the alert is trying to tell me about the underlying web page.

Chosen solution

You can use code in Stylish or add code to userChrome.css below the @namespace line to change the background color and the transparency.

Some examples (first is the current default; only use one):

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

tabmodalprompt { background-color: rgba(25, 25, 25, 0.5) !important; }
tabmodalprompt { background-color: rgba(224, 224, 224, 0.1) !important; }
tabmodalprompt { background-color: transparent !important; }

Read this answer in context 👍 1

All Replies (7)

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Looks like this CSS code:

  • chrome://global/skin/tabprompts.css
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cor-el, when I go to the address in your reply, I see the Tab Modal Prompt styles, and I see a value of .5 for the alpha channel, but I don't understand whether this means that it can or cannot be tweaked by the user. Can you please elaborate? Thanks!

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Chosen Solution

You can use code in Stylish or add code to userChrome.css below the @namespace line to change the background color and the transparency.

Some examples (first is the current default; only use one):

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

tabmodalprompt { background-color: rgba(25, 25, 25, 0.5) !important; }
tabmodalprompt { background-color: rgba(224, 224, 224, 0.1) !important; }
tabmodalprompt { background-color: transparent !important; }

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Perfect! Thank you, cor-el.

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You're welcome.

Which code did you decide to use?

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I used

tabmodalprompt

{ 
 background-color: rgba(224, 224, 224, 0.1) !important; 
}

Now that you've shown me the articles on creating a userChrome.css file, I can learn a lot more about customizing.

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Thanks for posting that code.

See also this mozillaZine forum thread with a lot of examples for Firefox 4.

"Fx4 .css tweaks":