blur of part of Background image with css

I use this Is it possible to use -webkit-filter: blur(); on background-image? solution to make blurry backgroung image and it works great! But I want to make some <div> over background and make it blurry. So background should be clear and blurry under <div> only. If I move blur filter on that div it became blur, but background image still clear.

HTML is simple:

<body>
   <div class = "background"></div>
   <div class = "content"></div>
</body>

CSS is:

.content{
    width: 70%;
    height: 70%;
    border:2px solid;
    border-radius:20px;
    position: fixed;
    top: 15%;
    left: 15%;
    z-index:10;
    background-color: rgba(168, 235, 255, 0.2);
    filter: blur(2px); 
    -webkit-filter: blur(2px);
    -moz-filter: blur(2px);
    -o-filter: blur(2px); 
    -ms-filter: blur(2px);
}
.background{
    width:100%;
    height:100%;
    background-image:url('http://www.travel.com.hk/region/time_95.jpg');
    z-index:0;
    position:absolute;
}

Here is example http://jsfiddle.net/photolan/8gVGR/

So I need to blur background under content div only with CSS.

If it has to be dynamic, you should have some trouble, but you can have somewhere to start with this :

HTML

<div class="background"></div>
<div class="mask">
    <div class="bluredBackground"></div>
</div>
<div class="content"></div>

CSS

.content {
    width: 70%;
    height: 70%;
    border:2px solid;
    border-radius:20px;
    position: fixed;
    top: 15%;
    left: 15%;
    z-index:10;
    background-color: rgba(168, 235, 255, 0.2);
}
.background {
    width:100%;
    height:100%;
    background-image:url('http://www.travel.com.hk/region/time_95.jpg');
    z-index:2;
    position:fixed;
}
.bluredBackground {
    width:100%;
    height:100%;
    display:block;
    background-image:url('http://www.travel.com.hk/region/time_95.jpg');
    z-index:1;
    position:absolute;
    top:-20%;
    left:-20%;
    padding-left:20%;
    padding-top:20%;
    -webkit-filter: blur(2px);
}
.mask {
    width: 70%;
    height: 70%;
    border:2px solid;
    border-radius:20px;
    position: fixed;
    top: 15%;
    left: 15%;
    z-index:10;
    overflow:hidden;
}

FIDDLE

use -webkit-filter: blur(2px) in .background div not in .content div.

Here is your updated code:

.content{
width: 70%;
height: 70%;
border:2px solid;
border-radius:20px;
position: fixed;
top: 15%;
left: 15%;
z-index:10;
background-color: rgba(168, 235, 255, 0.2);
filter: blur(2px); 
-moz-filter: blur(2px);
-o-filter: blur(2px); 
-ms-filter: blur(2px);
}

.background{
width:100%;
height:100%;
background-image:url('http://www.travel.com.hk/region/time_95.jpg');
z-index:0;
position:absolute;
 -webkit-filter: blur(2px);
}

来源：https://stackoverflow.com/questions/19375311/div-blur-of-part-of-background-image-with-css

标签

css

html

background

filter

blur

<div> blur of part of Background image with css