CSS opacity only to background color, not the text on it? [duplicate]

Question

Can I assign the opacity property to the background property of a div only and not to the text on it?

I've tried:

background: #CCC;
opacity: 0.6;

but this doesn't change the opacity.

Tso

For a cross browser method, see an earlier answer I gave: #4792590 It's basically rgba, but it works everywhere. – Jahnke

This question was asked in January -- #638421 – Chiffon

A second same January asked question here: #4791063 – Headwards

Custom properties enables you to do this in a similar way to SCSS and LESS background: rgba(var(--customColour), 60%) – Materiality

Answer 1

It sounds like you want to use a transparent background, in which case you could try using the rgba() function:

rgba(R, G, B, A)

R (red), G (green), and B (blue) can be either <integer>s or <percentage>s, where the number 255 corresponds to 100%. A (alpha) can be a <number> between 0 and 1, or a <percentage>, where the number 1 corresponds to 100% (full opacity).

RGBa example

background: rgba(51, 170, 51, .1)    /*  10% opaque green */ 
background: rgba(51, 170, 51, .4)    /*  40% opaque green */ 
background: rgba(51, 170, 51, .7)    /*  70% opaque green */ 
background: rgba(51, 170, 51,  1)    /* full opaque green */ 

A small example showing how rgba can be used.

As of 2018, practically every browser supports the rgba syntax.

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@adam Just so you know, this will not work in IE. – Reynoso

Dang..why is it always the IE that spoils the fun?! – Caird

It works fine in IE9+ ;o) – Larkins

its not woks in mozilla firefox – Dock

background-color: rgba(54, 25, 25, .5); works Chrome,Mozilla,IE 10 as well – Benito

css3pie implements this css3 feature for older browsers such as IE8 & IE9 (as well as many others, ie. rounded corners & gradients), see css3pie.com/forum/viewtopic.php?f=4&t=1133 – Virge

What if the background is an image and you want to adjust its opacity without affecting all of its children? – Bowse

Yes, using rgba() works in most cases, but it would be nice if there was a "background-opacity:" property in css, because when the "background-color:" is set dynamically (on the fly) as an input to a settings function in an admin appearance panel, which has been coded to use only rgb(), and you don't want to override that in your css, because then the dynamic input in your function would not work. In that case, the only way to add opacity is to modify html. If there was a "background-opacity" property, then no html code modifications would be necessary... – Igniter

any other way to use this with hex codes? – Damara

If you use SASS, transparentize allows you to reuse your RGB color variables and still apply an opacity: codepen.io/timharbour/pen/cBLqi – Oscillation

Is there any way to use hex codes in the rgba function (e.g. rgba(0xff, 0xc4, 0x27, .5) ? – Caesarean

Answer 2

The easiest way to do this is with 2 divs, 1 with the background and 1 with the text:

#container {
  position: relative;
  width: 300px;
  height: 200px;
}
#block {
  background: #CCC;
  filter: alpha(opacity=60);
  /* IE */
  -moz-opacity: 0.6;
  /* Mozilla */
  opacity: 0.6;
  /* CSS3 */
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
}
#text {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

<div id="container">
  <div id="block"></div>
  <div id="text">Test</div>
</div>

Rent

following property - "position: absolute;" is must in #text class for the effect to work. – Garden

But this will not be a good idea, in case we have another absolute positioned div who's position depends on parent relative element of #container – Uncle

And what happens when you need your #block opac background placement to be determined by your text? For instance: hovering over a promo block brings up text half the size of the promo block. The #block layer won't respond to the text height. – Freudberg

I like this answer than fiddling with rgba since it's better supported. But why does #text have to be position absolute? With the #block in position absolute, it's out of the flow and won't affect the other elements in the page. – Schaffel

Answer 3

For Less users only:

If you don't like to set your colors using RGBA, but rather using HEX, there are solutions.

You could use a mixin like:

.transparentBackgroundColorMixin(@alpha,@color) {
  background-color: rgba(red(@color), green(@color), blue(@color), @alpha);
}

And use it like:

.myClass {
    .transparentBackgroundColorMixin(0.6,#FFFFFF);
}

Actually this is what a built-in Less function also provide:

.myClass {
    background-color: fade(#FFFFFF, 50%);
}

See How do I convert a hexadecimal color to rgba with the Less compiler?

Katherinkatherina

You could also achieve this without Less or mixins by modifying the end of the string of the hex value with inline style w3schools.com/cssref/css_colors_legal.asp – Lynnalynne

Thanks! I am using SCSS and did something like this: background-color: rgba(red($primary), green($primary), blue($primary), 0.25); – Officiate

Answer 4

I had the same problem. I want a 100% transparent background color. Just use this code; it's worked great for me:

rgba(54, 25, 25, .00004);

You can see examples on the left side on this web page (the contact form area).

Sestina

If you actually want 100% transparent, why aren't you using rgba(54, 25, 25, 0);? Most modern browsers won't round until the 15th decimal, but the visual difference is most likely pretty minimal between your 99.996% transparent and just using 100% transparent. – Agamic

Answer 5

My trick is to create a transparent .png with the color and use background:url().

Faxun

That's the best solution if you're dealing with legacy browsers, IMO. – Opinionated

Answer 6

This will work with every browser

div {
    -khtml-opacity: .50;
    -moz-opacity: .50;
    -ms-filter: ”alpha(opacity=50)”;
    filter: alpha(opacity=50);
    filter: progid:DXImageTransform.Microsoft.Alpha(opacity=0.5);
    opacity: .50;
}

If you don't want transparency to affect the entire container and its children, check this workaround. You must have an absolutely positioned child with a relatively positioned parent to achieve this. CSS Opacity That Doesn’t Affect Child Elements

Check a working demo at CSS Opacity That Doesn't Affect "Children"

Reynoso

This affects the foreground. OP asked specifically for background only. – Hour

@Hour any solution for background only? but using rgb and alpha in different css lines – Dorm

Answer 7

For anyone coming across this thread, here's a script called thatsNotYoChild.js that I just wrote that solves this problem automatically:

http://www.impressivewebs.com/fixing-parent-child-opacity/

Basically, it separates children from the parent element, but keeps the element in the same physical location on the page.

Cristionna

Answer 8

A great way to do this would be to use CSS 3 indeed.

Create a div width a class - e.g. supersizer on top of your page:

Then set following CSS properties:

  .supersizer {
    background: url("http://fc06.deviantart.net/fs70/f/2012/099/d/f/stackoverflow_16x16_icon_by_muntoo_stock-d4vl2v4.png") no-repeat center center fixed;
    width: 100%;
    height: 100%;
    position: fixed;
    z-index: -1;
    opacity: 0.5;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    top: 0;
  }

<div class="supersizer"></div>

Ultracentrifuge

Answer 9

The easiest solution is to create 3 divs. One that will contain the other 2, the one with transparent background and the one with content. Make the first div's position relative and set the one with transparent background to negative z-index, then adjust the position of the content to fit over the transparent background. This way you won't have issues with absolute positioning.

Chink

Each one of 3 divs should be set to relative positioning so then they can be moved and adjusted inside the parent div, and also the parent div (if needed) moved in context of the whole page. Div with transparent background and the one with content should not contain each other. They shold be sibiling in first div. – Chink

Answer 10

Use:

background:url("location of image"); // Use an image with opacity

This method will work in all browsers.

Sweater

I don't think the OP wanted to use an image, though it doesn't state that. Didn't vote down for this, just trying to clarify. – Protohuman

Answer 11

You can't. You have to have a separate div that is just that background, so that you can only apply the opacity to that.

I tried doing this recently, and since I was already using jQuery, I found the following to be the least hassle:

1. Create the two different divs. They'll be siblings, not contained in each other or anything.
2. Give the text div a solid background color, because that will be the JavaScript-less default.
3. Use jQuery to get the text div's height, and apply it to the background div.

I'm sure there's some kind of CSS ninja way to do all this with only floats or something, but I didn't have the patience to figure it out.

Bloodletting

background: rgba(54, 25, 25, .5); must be the css ninja you are talking about. :) – Mandel