CSS Box Shadow Bottom Only

Do this:

box-shadow: 0 4px 2px -2px gray;

It's actually much simpler, whatever you set the blur to (3rd value), set the spread (4th value) to the negative of it.

Box shadow for bottom side only

You can do the following after adding class one-edge-shadow or use as you like.

.one-edge-shadow {
    -webkit-box-shadow: 0 8px 6px -6px black;
       -moz-box-shadow: 0 8px 6px -6px black;
            box-shadow: 0 8px 6px -6px black;
}

Source

CSS Box Shadow - Top and Bottom Only

As Kristian has pointed out, good control over z-values will often solve your problems.

If that does not work you can take a look at CSS Box Shadow Bottom Only on using overflow hidden to hide excess shadow.

I would also have in mind that the box-shadow property can accept a comma-separated list of shadows like this:

box-shadow: 0px 10px 5px #888, 0px -10px 5px #888;

This will give you some control over the "amount" of shadow in each direction.

Have a look at http://www.css3.info/preview/box-shadow/ for more information about box-shadow.

Hope this was what you were looking for!

How to create a drop shadow only on one side of an element?

UPDATE 4

Same as update 3 but with modern css (=fewer rules) so that no special positioning on the pseudo element is required.

#box {
    background-color: #3D6AA2;
    width: 160px;
    height: 90px;
    position: absolute;
    top: calc(10% - 10px);
    left: calc(50% - 80px);
}

.box-shadow:after {
    content:"";
    position:absolute;
    width:100%;
    bottom:1px;
    z-index:-1;
    transform:scale(.9);
    box-shadow: 0px 0px 8px 2px #000000;
}

<div id="box" class="box-shadow"></div>

How do I ONLY add a box-shadow to the bottom with the following css?

Decrease the spread distance based on the blur radius (i.e. spread distance needs to compensate for addition of blur). Don't forget to adjust offset as well to compensate for reduction in spread.

box-shadow: 0px 4px 5px -3px #888;

http://jsfiddle.net/p469p/

You also only need box-shadow. Mozilla and Webkit have supported it for a long time.

And for more informations see drop shadow only bottom css3

Have an issue with box-shadow Inset bottom only

Use a negative value for the fourth length which defines the spread distance. This is often overlooked, but supported by all major browsers. See this Fiddle for the result.

div {  background: red;  height: 100px;  width: 200px;  -moz-box-shadow: inset 0 -10px 10px -10px #000000;  -webkit-box-shadow: inset 0 -10px 10px -10px #000000;  box-shadow: inset 0 -10px 10px -10px #000000;}

<div></div>

How to get box-shadow on left & right sides only

NOTE: I suggest checking out @Hamish's answer below; it doesn't involve the imperfect "masking" in the solution described here.

You can get close with multiple box-shadows; one for each side

box-shadow: 12px 0 15px -4px rgba(31, 73, 125, 0.8), -12px 0 8px -4px rgba(31, 73, 125, 0.8);

http://jsfiddle.net/YJDdp/

Edit

Add 2 more box-shadows for the top and bottom up front to mask out the that bleeds through.

box-shadow: 0 9px 0px 0px white, 0 -9px 0px 0px white, 12px 0 15px -4px rgba(31, 73, 125, 0.8), -12px 0 15px -4px rgba(31, 73, 125, 0.8);

http://jsfiddle.net/LE6Lz/

CSS Box Shadow Bottom Only