How do I give text or an image a transparent background using CSS?

There is a trick to minimize the markup: Use a pseudo element as the background and you can set the opacity to it without affecting the main element and its children:

DEMO

Output:

https://i.stack.imgur.com/8lK67.jpg

Relevant code:

p { position: relative; } p:after { content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: #fff; -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=50)"; opacity: .6; z-index: -1; } /*** The following is just for demo styles ***/ body { background: url('http://i.imgur.com/k8BtMvj.jpg') no-repeat; background-size: cover; } p { width: 50%; padding: 1em; margin: 10% auto; font-family: arial, serif; color: #000; } img { display: block; max-width: 90%; margin: .6em auto; }

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed a ligula ut nunc dignissim molestie.

Browser support is Internet Explorer 8 and later.

pseudo elements

opacity

It's better to use a semi-transparent .png.

Just open Photoshop, create a 2x2 pixel image (picking 1x1 can cause an Internet Explorer bug!), fill it with a green color and set the opacity in "Layers tab" to 60%. Then save it and make it a background image:

<p style="background: url(green.png);">any text</p>

It works cool, of course, except in lovely Internet Explorer 6. There are better fixes available, but here's a quick hack:

p {
    _filter: expression((runtimeStyle.backgroundImage != 'none') ? runtimeStyle.filter = 'progid:DXImageTransform.Microsoft.AlphaImageLoader(src='+currentStyle.backgroundImage.split('\"')[1]+', sizingMethod=scale)' : runtimeStyle.filter,runtimeStyle.backgroundImage = 'none');
}

This method allows you to have an image in the background and not only a solid color, and can be used to have transparency on other attributes such as borders. No transparent PNG images are required.

Use :before (or :after) in CSS and give them the opacity value to leave the element at its original opacity. Thus you can use :before to make a faux element and give it the transparent background (or borders) you want and move it behind the content you want to keep opaque with z-index.

An example (fiddle) (note that the DIV with class dad is just to provide some context and contrast to the colors, this extra element is actually not needed, and the red rectangle is moved a bit down and to the right to leave visible the background behind the fancyBg element):

<div class="dad">
    <div class="fancyBg">
        Test text that should have solid text color lets see if we can manage it without extra elements
    </div>
</div>

with this CSS:

.dad {
    background: lime; border: 1px double black; margin: 1ex 2ex;
    padding: 0.5ex; position: relative; -k-z-index: 5;
}
.fancyBg {
    border: 1px dashed black; position: relative; color: white; font-weight: bold;
    z-index: 0; /*background: black;*/
}
.fancyBg:before {content:'-'; display: block;
    position: absolute; background: red; opacity: .5;
    top: 2ex; right: -2ex; bottom: -2ex; left: 2ex;
    /*top: 0; right: 0; bottom: 0; left: 0;*/
    z-index: -1;
}

In this case .fancyBg:before has the CSS properties you want to have with transparency (red background in this example, but can be an image or borders). It's positioned as absolute to move it behind .fancyBg (use values of zero or whatever is more appropriate for your needs).

The easiest method would be to use a semi-transparent background PNG image.

You can use JavaScript to make it work in Internet Explorer 6 if you need to.

I use the method outlined in Transparent PNGs in Internet Explorer 6.

Other than that, you could fake it using two side-by-side sibling elements - make one semi-transparent, then absolutely position the other over the top.

Almost all these answers assume the designer wants a solid color background. If the designer actually wants a photo as the background the only real solution at the moment is JavaScript like the jQuery Transify plugin mentioned elsewhere.

What we need to do is join the CSS working group discussion and make them give us a background-opacity attribute! It should work hand in hand with the multiple-backgrounds feature.

The problem is, that the text actually has full opacity in your example. It has full opacity inside the p tag, but the p tag is just semi-transparent.

You could add an semi-transparent PNG background image instead of realizing it in CSS, or separate text and div into two elements and move the text over the box (for example, negative margin).

Otherwise it won't be possible.

Just like Chris mentioned: if you use a PNG file with transparency, you have to use a JavaScript workaround to make it work in the pesky Internet Explorer...

Here's how I do this (it might not be optimal, but it works):

Create the div that you want to be semi-transparent. Give it a class/id. Leave it empty, and close it. Give it a set height and width (say, 300 pixels by 300 pixels). Give it an opacity of 0.5 or whatever you like, and a background color.

Then, directly below that div, create another div with a different class/id. Create a paragraph inside it, where you'll place your text. Give the div position: relative, and top: -295px (that's negative 295 pixels). Give it a z-index of 2 for good measure, and make sure its opacity is 1. Style your paragraph as you like, but make sure the dimensions are less than that of the first div so it doesn't overflow.

That's it. Here's the code:

.trans { opacity: 0.5; height: 300px; width: 300px; background-color: orange; } .trans2 { opacity: 1; position: relative; top: -295px; } .trans2 p { width: 295px; color: black; font-weight: bold; }

This works in Safari 2.x, but I don't know about Internet Explorer.

If you are a Photoshop guy, you can also use:

 #some-element {
  background-color: hsla(170, 50%, 45%, 0.9); // **0.9 is the opacity range from 0 - 1**
 }

Or:

#some-element {
  background-color: rgba(170, 190, 45, 0.9); // **0.9 is the opacity range from 0 - 1**
}

Here is a jQuery plugin that will handle everything for you, Transify (Transify - a jQuery plugin to easily apply transparency / opacity to an element’s background).

I was running into this problem every now and then, so I decided to write something that would make life a lot easier. The script is less than 2 KB and it only requires one line of code to get it to work, and it will also handle animating the opacity of the background if you like.

A while back, I wrote about this in Cross Browser Background Transparency With CSS.

Bizarrely Internet Explorer 6 will allow you to make the background transparent and keep the text on top fully opaque. For the other browsers I then suggest using a transparent PNG file.

Opacity of background, but not the text has some ideas. Either use a semi-transparent image, or overlay an additional element.

CSS 3 has an easy solution of your problem. Use:

background-color:rgba(0, 255, 0, 0.5);

Here, rgba stands for red, green, blue, and alpha value. The green value is obtained because of 255 and half transparency is obtained by a 0.5 alpha value.

In order to make the background of an element semi-transparent, but have the content (text & images) of the element opaque, you need to write CSS code for that image, and you have to add one attribute called opacity with minimum value.

For example,

.image {
   position: relative;
   background-color: cyan;
   opacity: 0.7;
}

// The smaller the value, the more it will be transparent, ore the value less will be transparency.

If you're using Less, you can use fade(color, 30%).

background-color: rgba(255, 0, 0, 0.5); as mentioned above is the best answer simply put. To say use CSS 3, even in 2013, is not simple because the level of support from various browsers changes with every iteration.

While background-color is supported by all major browsers (not new to CSS 3) [1] the alpha transparency can be tricky, especially with Internet Explorer prior to version 9 and with border color on Safari prior to version 5.1. [2]

Using something like Compass or SASS can really help production and cross platform compatibility.

[1] W3Schools: CSS background-color Property

[2] Norman's Blog: Browser Support Checklist CSS3 (October 2012)

You can solve this for Internet Explorer 8 by (ab)using the gradient syntax. The color format is ARGB. If you are using the Sass preprocessor you can convert colors using the built-in function "ie-hex-str()".

background: rgba(0,0,0, 0.5);
-ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr='#80000000', endColorstr='#80000000')";

<div align="center" style="width:100%;height:100%;background:white;opacity:0.5;position:absolute;z-index:1001">
    <img id="search_img" style="margin-top:20%;" src="../resources/images/loading_small.gif">
</div>

http://jsfiddle.net/x2ukko7u/?

There's an easier solution to put an overlay over an image on the same div. It's not the right use of this tool. But works like a charm to make that overlay using CSS.

Use an inset shadow like this:

box-shadow: inset 0 0 0 1000px rgba(255, 255, 255, 0.9);

That's all :)

You can use the opacity value appended to the hexadecimal value:

background-color: #11ffeeaa;

In this example aa is the opacity. An opacity of 00 means transparent and ff means solid color.

The opacity is optional, so you can use the hexadecimal value as always:

background-color: #11ffee;

You can also use the old way with rgba():

background-color: rgba(117, 190, 218, 0.5);

And the background shorthand if you want to make sure that the background has no other styles, like images or gradients:

background: #11ffeeaa;

From the Mozilla's specification (https://developer.mozilla.org/en-US/docs/Web/CSS/background-color):

/* Keyword values */
background-color: red;
background-color: indigo;

/* Hexadecimal value */
background-color: #bbff00;    /* Fully opaque */
background-color: #bf0;       /* Fully opaque shorthand */
background-color: #11ffee00;  /* Fully transparent */
background-color: #1fe0;      /* Fully transparent shorthand  */
background-color: #11ffeeff;  /* Fully opaque */
background-color: #1fef;      /* Fully opaque shorthand  */

/* RGB value */
background-color: rgb(255, 255, 128);        /* Fully opaque */
background-color: rgba(117, 190, 218, 0.5);  /* 50% transparent */

/* HSL value */
background-color: hsl(50, 33%, 25%);         /* Fully opaque */
background-color: hsla(50, 33%, 25%, 0.75);  /* 75% transparent */

/* Special keyword values */
background-color: currentcolor;
background-color: transparent;

/* Global values */
background-color: inherit;
background-color: initial;
background-color: unset;

I normally use this class for my work. It's pretty good.

.transparent { filter: alpha(opacity=50); /* Internet Explorer */ -khtml-opacity: 0.5; /* KHTML and old Safari */ -moz-opacity: 0.5; /* Firefox and Netscape */ opacity: 0.5; /* Firefox, Safari, and Opera */ }

It worked for me when using the format #AARRGGBB so the one working for me was #1C00ff00. Give it a try, because I have seen it working for some and not working for someone else. I am using it in CSS.

Since a lot of people will arrive here wanting to know how to adjust the opacity of any element (not just backgrounds), it's as simple as adding opacity: 0.2 (or whatever number between 0 and 1 you desire) to that element's CSS.

Example

.myclass {
  color: #eb4746;
  opacity: 0.2;
}

This can be used in backgrounds and in headers, paragraphs etc.

I agree with all above answers and rgba is the way to go. In my case, I was provided with a hex background programmatically, so I will have to generate my own rgba based on the hex code. I created a modified version of Mr. Down's answer to convert hex to rgba

function hexToRgba(hex,alpha) {
    // Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
    var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
    hex = hex.replace(shorthandRegex, function(m, r, g, b) {
      return r + r + g + g + b + b;
    });

    var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
    if(result!=null){
      const r = parseInt(result[1], 16);
      const g = parseInt(result[2], 16);
      const b = parseInt(result[3], 16);
      //
      return `rgba(${r},${g},${b},${alpha})`;

    }
    return null;
  }

I think this gives you desired output:

div {
  width: 200px;
  height: 200px;
  display: block;
  position: relative;
}

div::after {
  content: "";
  background: url(image.jpg);
  opacity: 0.5;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  position: absolute;
  z-index: -1;   
}

This gives the desired result -

body {
    background-image: url("\images\dark-cloud.jpg");
    background-size: 100% 100%;
    background-attachment: fixed;
    opacity: .8;
}

Setting the opacity of the background.