Using a Div to Blur an Image Behind It

Blur Behind Div CSS

backdrop-filter: blur(10px);

It will blur area behind the element.

using a div to blur an image behind it?

Not with CSS on its own, but you can pull a similar effect off with Canvas and the StackBlurforCanvas library. See this

UPDATE: Looks like backdrop-filter was recently introduced to Webkit nightly, so eventually we'll be able to do this with CSS only. Yay!

How to blur background image of div, without blurring the remaining site or the content of the div

Here is the solution

<body><header class="intro">
  <div class="background-image"></div>
  <div class="intro-body">
    <div class="container">
      <div class="row">
        <div class="col-md-8 col-md-offset-2">
          <h1 class="brand-heading">Grayscale</h1>
          <p class="intro-text">A free, responsive, one page Bootstrap theme.
            <br>Created by Start Bootstrap.</p>
          <a href="#about" class="btn btn-circle page-scroll">
            <i class="fa fa-angle-double-down animated"></i>
          </a>
        </div>
      </div>
    </div>
  </div>
</header>
</body>

Css :

body {
    width: 100%;
    height: 100%;
    font-family: "Lora", "Helvetica Neue", Helvetica, Arial, sans-serif;
    color: white;
    background-color: black;
    margin: 0;
    padding: 0;
}

.intro {
    display: table;
    width: 100%;
    height: auto;
    padding: 100px 0;
    text-align: center;
    color: white;
}

.intro .background-image {
    z-index: -1;
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: url(https://wallpaperbrowse.com/media/images/html-color-codes-color-tutorials-hero-00e10b1f.jpg);
    -webkit-filter: blur(10px);
    filter: blur(10px);
}

.intro .intro-body {
  z-index: 9999;
  display: table-cell;
  vertical-align: middle;
}

How to blur ALL elements behind a div (text, shapes, buttons - not just the background image). CSS only if possible

I blurred by background image externally, and then took out the blur in css (as people told me to for performance reasons in the comments).

After doing that, and without changing anything else, now my blur works on the navbar! It seems to be that the background blur was messing up a bunch of stuff.

Thank you for the help in the comments!

P.S. The fixed positioning that didn't work before now works?!?

To blur an element with no background image by css

What you are looking for is backdrop-filter

body {  background-image: url(https://i.picsum.photos/id/174/800/800.jpg);  background-attachment: fixed;  background-size: cover;  height: 100vh;  margin:0;  position: relative;}

.parent-div {  position: relative;  height:50vh;  backdrop-filter: blur(10px);  -webkit-backdrop-filter: blur(10px);}

<div class=" parent-div">  <div class=" child-div">    <h4 class=" text-light">Hello world!!</h4>  </div></div><div class=" parent-div">  <div class=" child-div">    <h4 class=" text-light">Hello world!!</h4>  </div></div>

How to apply a CSS filter to a background image

Check out this pen.

You will have to use two different containers, one for the background image and the other for your content.

In the example, I have created two containers, .background-image and .content.

Both of them are placed with position: fixed and left: 0; right: 0;. The difference in displaying them comes from the z-index values which have been set differently for the elements.

.background-image {
  position: fixed;
  left: 0;
  right: 0;
  z-index: 1;
  display: block;
  background-image: url('https://i.imgur.com/lL6tQfy.png');
  width: 1200px;
  height: 800px;
  -webkit-filter: blur(5px);
  -moz-filter: blur(5px);
  -o-filter: blur(5px);
  -ms-filter: blur(5px);
  filter: blur(5px);
}

.content {
  position: fixed;
  left: 0;
  right: 0;
  z-index: 9999;
  margin-left: 20px;
  margin-right: 20px;
}

<div class="background-image"></div>
<div class="content">
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis aliquam erat in ante malesuada, facilisis semper nulla semper. Phasellus sapien neque, faucibus in malesuada quis, lacinia et libero. Sed sed turpis tellus. Etiam ac aliquam tortor, eleifend
    rhoncus metus. Ut turpis massa, sollicitudin sit amet molestie a, posuere sit amet nisl. Mauris tincidunt cursus posuere. Nam commodo libero quis lacus sodales, nec feugiat ante posuere. Donec pulvinar auctor commodo. Donec egestas diam ut mi adipiscing,
    quis lacinia mauris condimentum. Quisque quis odio venenatis, venenatis nisi a, vehicula ipsum. Etiam at nisl eu felis vulputate porta.</p>
  <p>Fusce ut placerat eros. Aliquam consequat in augue sed convallis. Donec orci urna, tincidunt vel dui at, elementum semper dolor. Donec tincidunt risus sed magna dictum, quis luctus metus volutpat. Donec accumsan et nunc vulputate accumsan. Vestibulum
    tempor, erat in mattis fringilla, elit urna ornare nunc, vel pretium elit sem quis orci. Vivamus condimentum dictum tempor. Nam at est ante. Sed lobortis et lorem in sagittis. In suscipit in est et vehicula.</p>
</div>