CSS opacity within an image

Question

What's the best way (if any) to make the inside box transparent so the image can be seen with no opacity (clear image) and the rest of the outer box opaque. So far this is what I'm doing:

<style>
#a {
  background-color: black;
  float: left;
} #b {
    opacity : 0.4;
    filter: alpha(opacity=40); 
} #div {
    position: absolute;
    height: 30px;
    width: 30px;
    top: 90px;
    left: 90px;
    border: 1px solid #FFF;
    background: transparent;
}
</style>

<div id="a">
  <div id="b">    
    <img src="http://clagnut.com/images/ithaka.jpg" />
  </div>
</div>
<div id="div"></div>

Any ideas? thx

Answer 1

The maximum opacity of an element is the opacity of its parent element. So if div#b has an opacity of 40%, if his children have 100% opacity in style they will also be 40% absolute opacity.

To accomplish what you're describing (at least what I think you're describing), one way could be to have both the transparent wrapper and the image children of a parent div with relative positioning. You can absolutely position both of the children inside of that wrapper so that the image shows up on top of the transparent box.

Edit: Here is the code for the effect you are describing. My example has a 480 x 320 image, and a 30-pixel border:

<style>
    #back {background-image:url(mypicture.jpg);
               width:480px;
               height:320px;
               position:relative;}
    #middle {position:absolute;
                 width:480px;
                 height:320px;
                 background-color:#000;
                 opacity:0.4;
                 filter:alpha(opacity=40);
                 top:0;
                 left:0;}
    #front {position:absolute;
                width:420px; /* 30px border on left & right */
                height:260px; /* 30px border on top & bottom */
                background-image:url(mypicture.jpg);
                background-position:-30px -30px; /* compensate for the border */
                top:30px;
                left:30px;}
</style>

<div id="back">
    <div id="middle">
    </div>
    <div id="front">
    </div>
</div>

Answer 2

If I understand you correctly, try using just one div (i.e. get rid of the outer one with ID "a") and setting a colored border around it. Or you could get more flexibility by "faking" a border using 4 divs for the left, right, top, and bottom edges and 4 more for the corners.

It's kind of hard to know what you mean without an example page, or screenshots of what you expect and what you're actually getting.

EDIT: I was about to edit in basically the same thing Rex M wrote. Here's another (although idealistically inferior) way to do it:

<style>
#a {
    float: left;
    position: relative;
}
div.overlay {
    opacity: 0.4;
    background-color: black;
    position: absolute;
}
#t {
    left: 0; top: 0; height: 90px; width: 450px;
}
#b {
    left: 0; top: 120px; height: 218px; width: 450px;
}
#l {
    left: 0; top: 90px; height: 30px; width: 90px;
}
#r {
    left: 120px; top: 90px; height: 30px; width: 330px;
}
</style>
<div id="a">
    <div id="t" class="overlay"></div>
    <div id="b" class="overlay"></div>
    <div id="l" class="overlay"></div>
    <div id="r" class="overlay"></div>
    <img src="http://clagnut.com/images/ithaka.jpg">
</div>