CODEWITHSUNDEEP
cssfirefoxcss-position
user2250471
user2250471

Reputation: 1112

CSS - "position: fixed" acting like "absolute" in Firefox

I've been building a website in Safari, and I've just tested it in Firefox and my fixed navigation elements are behaving as if they're position is absolute.

#navigation {
    display: block;
    width: 100%;
    height: 50px;
    position: fixed;
    left: 0px;
    bottom: 0px;
    text-align: center;
    z-index: 99000;
}

This is the CSS I have for the primary navigation wrapper (it's a bottom nav.). In Webkit, it works perfectly: that is, it sticks to the bottom of the window regardless. In firefox, it positions itself at the end of the tags, so, for example, on a long page, I'd have to scroll down just to see it. It is acting as if it's absolute.

I also have a sidebar navigation.

.slidebar {
    display: block;
    position: fixed;
    left: -1px;
    top: -1px;
    width: 1px;
    height: 100%;
    overflow: hidden;
    -webkit-transition: all 300ms ease;
    -moz-transition: all 300ms ease;
    -o-transition: all 300ms ease;
    -ms-transition: all 300ms ease;
    transition: all 300ms ease;
    z-index: 99998;
}

This sidebar is also acting as if it's absolute - that is, it is positioning itself off the screen properly, but it's elongating <body> and thus the horizontal scrollbar appears. The height: 100%; is also responding to the <body> height and not the window height, so, for example, my <header> has a top margin of 20px, and the slidebar observes that margin too (the body has 0 margin). Likewise, instead of the height: 100%; ending at the bottom of the window, it ends at the bottom of the <body>, factoring in the footer's bottom margin.

I cannot understand for the life of me why this is happening. Element inspection shows all the properties are loading fine, and in Chrome and Safari it works. It worked initially, and it worked the last time I even edited either navigation, but it has since stopped working since I built other, irrelevant, parts of the site.

http://www.upprise.com/demo.php - click the Envelope icon to see the sidebar

Upvotes: 21

Views: 27572

Answers (10)

matthewiannowlin
matthewiannowlin

Reputation: 125

I had this same issue in Chrome, and the backdrop-filter property on the parent was causing the issue. I remove that property and position: fixed behaves normally.

Upvotes: 1

Javi Villar
Javi Villar

Reputation: 117

I had the same problem. In my case, the root of the problem was an ANIMATION on the body, so take care with "animations" on elements that are parents of the element that you want to be "position: fixed".

I don't know why this happen...

Here you can see more people talking about this issue with position: fixed and animation

Upvotes: 0

M.A Shahbazi
M.A Shahbazi

Reputation: 1081

After 5 hours of debugging, if you are using tailwindcss and you have drop-shadow-* (pay attention it's not shadow-*) class on one of your parent elements, it will cause the fixed elements within that element to act like they're absolute positioned.

Not sure why that is happening, maybe due to fact that tailwindcss is using lots of combined CSS variables.

Here's an example of what gets generated with tailwindcss drop-shadow-* utility, seems like filter property on one of the parent elements causes the same unexpected behaviour as transforms:

.drop-shadow-lg {
    --tw-drop-shadow: drop-shadow(0 10px 8px rgba(0, 0, 0, 0.04)) drop-shadow(0 4px 3px rgba(0, 0, 0, 0.1));
    filter: var(--tw-filter);
}

Upvotes: 1

Kevin Weber
Kevin Weber

Reputation: 261

I solved the issue by moving the element that uses position: fixed; out of its original parent element that uses transform: translateX(-50%);.

Thus...

<div class="transformed-container">
   <div="fixed-element"></div>
</div>

...became...

<div class="transformed-container"></div>

<div class="fixed-element"></div>

Two things led me to this conclusion:

  1. @Pankaj's answer shows that the translate value can cause an issue.
  2. @Wildhoney's comment to another answer references an explanation of the underlying cause: http://meyerweb.com/eric/thoughts/2011/09/12/un-fixing-fixed-elements-with-css-transforms/

Upvotes: 4

Beltran
Beltran

Reputation: 21

I needed to remove some css classes from the superior container of the fixed-on-scroll element that had a transition, from the animateCSS library.

$(window).on('scroll', function () {
     if (distance <= 65) {
        $('#my-contaniner').removeClass('animated fadeInLeft'); //delete problematic classes for FF
Add your code
 });

Maybe it helps

Upvotes: 1

Pankaj
Pankaj

Reputation: 3712

I had the exact same problem, turns out the following CSS property of a parent element was causing the problem.

transform: translate3d(0px, 0px, 0px);

Upvotes: 26

user2250471
user2250471

Reputation: 1112

Through the process of elimination I was able to determine that having the following in my body was causing all the problems with fixed divs in Firefox:

-o-backface-visibility: hidden;
-moz-backface-visibility: hidden;
-webkit-backface-visibility: hidden;
backface-visibility: hidden;

I had originally added this code to prevent flickering in certain CSS transitions throughout the site, but I guess I'll have to add it to each individual class now.

Upvotes: 22

Ryan Wheale
Ryan Wheale

Reputation: 28460

It appears that some browsers will will apply fixed positioning relative to the window, while Firefox is applying it relative to the <body />. You need to make your body 100% tall:

body {
    height: 100%;
}

But the margin from your .header is collapsing outside of the body element. Change this:

margin: 25px auto;

to this:

margin: 0 auto; /* updated - thanks JoshC */
padding: 25px auto;

Upvotes: 4

Patrick
Patrick

Reputation: 327

The problem seems to be in your body, i've added width:100%; height:100%; and overflow:hidden; to it in my fire fox and it looked just fine, except for the bottom menu-bar that went half of it's height over the bottom.

Upvotes: 2

Josh Crozier
Josh Crozier

Reputation: 241278

Not sure why the browsers were rendering differently, though the solution is pretty simple. You need to give the parent elements (html/body) a height of 100% in order to fill the entire page. It seems like FF rendered the fixed elements at the bottom of the contents as opposed to the bottom of the window. Adding the following will make it work across browsers:

html, body {
    height: 100%;
}

In addition, you should also use padding on .header element as opposed to a margin. This will solve another issue.

.header {
    margin: 0 auto;    /* use a value of 0 rather than 25px */
    padding: 25px 0;
}

I tested all this in the browser, it will work in FF now. It should also render properly in Chrome and others.

Upvotes: 1

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