How to make edgy corners with css - html

Question

Does anyone know how to make edgy corners like in the following below? See how the edge wraps around the corner. I would like to know the term as well (if any). cross browser support (IE8 and up, bonus IE7) is a must. Thanks for any help.

Answer 1

Check out this tutorial. I don't know how crossbrowser compatible it is (as it is CSS3), but it achieves the effect you want.
HTML:
<div>
<h2></h2>
</div>
CSS:
div {
width: 200px;
padding: 50px;
margin: 0 auto;
border: 1px solid #333;
}
h2 {
position: relative;
width: 50%;
height: 50px;
margin: 30px 10px 10px -70px;
background-color: orange;
}
h2:after {
content: ' ';
position: absolute;
width: 0;
height: 0;
left: 0px;
top: 100%;
border-width: 5px 10px;
border-style: solid;
border-color: #666 #666 transparent transparent;
}
JS Fiddle Example

Answer 2

.box{
background: #666;
border: 4px solid #fff;
box-shadow: 0px 0px 20px #000;
width: 200px;
height: 200px;
margin: 40px auto;
position: relative;
}
.ribbon{
background: #FFA500;
position: absolute;
width: 100%;
top: 20px;
left: -20px;
height: 20px;
padding-right: 20px;
}
.ribbon::before{
content: '';
position: absolute;
left: 0px;
top: 20px;
width: 0px;
height: 0px;
border-style: solid;
border-width: 0 16px 10px 0;
border-color: transparent #FFA500 transparent transparent;
z-index: -5;
}
HTML:
<div class="box">
<div class="ribbon"></div>
</div>
(DEMO)
I don't think IE 7/8 support the ::before pseudo-element, so if you want IE compatibility add another element and put ::before styles on it :)

Answer 3

That edgy corner is only a div with a triangle actually, you only need ONE element to do it.
<div id="myCorner"></div>
myCorner will be the div, and myCorner:after will be the triangle.
Check it out : http://jsfiddle.net/Starx/Xp6E7/2/
#myCorner
{
width:100px;
height:70px;
background-color:orange;
-webkit-box-shadow: 0 4px 5px -3px black;
-moz-box-shadow: 0 4px 5px -3px black;
box-shadow: 0 4px 5px -3px black;
position:relative;
}
#myCorner:after
{
content:"";
position:absolute;
left: 0;
top:100%;
width: 0px;
height: 0px;
border-style:solid;
border-width: 5px 10px;
border-color: orange orange transparent transparent;
z-index: -1;
}