draw angular side / parallelogram using CSS

Question

Need to draw angular sides of menubar as

inner content may be the some labels or links.

Answer 1

How about using CSS3 transform skew?

Demo

.shape { 
    width: 200px; 
    height: 50px; 
    -webkit-transform: skew(30deg); 
    -moz-transform: skew(30deg); 
    transform: skew(30deg);
    background: #000;
    margin: 20px;
}

Nothing much to explain here, it's a simple div element, which I've skewed by 30deg which will result in the shape you expected.

Note: It's a CSS3 property, so older browsers, as well as IE will spoil your things, make sure you use CSS3 Pie.

---

Other way to achieve this is by using :after and :before pseudo and CSS Triangles along with content property.

Demo 2 (Kept red triangles for demo purpose)

Demo 3 (Color Changed)

Demo 4 (As you commented, you need to use top: 0; for :before and :after pseudo as well, because when you add text, it will shift both the triangles from the top. So inorder to prevent that, use top: 0;)

Here, am using a simple div element and placing 2 CSS triangles which are positioned absolute to the container. This is more compatible than above, if you are going for a NON CSS3 solution, you can choose this. Make sure you use display: block; for :before as well as :after. And ofcourse you can merge the common styles but I've kept both separate, so that you can get easability to customize them separately.

 .shape { 
    width: 200px; 
    height: 50px; 
    background: #000;
    margin: 50px;
    position: relative;
}

.shape:before {
    display: block;
    content: "";
    height: 0;
    width: 0;
    border: 25px solid #f00;
    border-bottom: 25px solid transparent;
    border-left: 25px solid transparent;
    position: absolute;
    left: -50px;
}

.shape:after {
    display: block;
    content: "";
    height: 0;
    width: 0;
    border: 25px solid #f00;
    border-top: 25px solid transparent;
    border-right: 25px solid transparent;
    position: absolute;
    right: -50px;
}

Answer 2

HTML

<div class="shape">
    <div class="text">
           text goes here
    </div>
 </div>

CSS

 .shape { 
    width: 200px; 
    height: 30px; 
    -webkit-transform: skew(30deg); 
    -moz-transform: skew(30deg); 
    transform: skew(30deg);
    background: #000;
    margin: 20px;
    color:#fff;
}
.text{
    width: 150px; 
    height: 30px; 
    margin:0px auto;
    -webkit-transform: skew(-30deg); 
    -moz-transform: skew(-30deg); 
    transform: skew(-30deg);
     color:#fff;
}

Answer 3

One major gripe I have with using triangular borders is that there is no easy way to have multiple triangles with different colours, even using javascript [because JS can't access the pseudo-elements :before and :after], the alternative being that I use 3 divs, align them properly, and give all of them the same colour, etc... Too much hassle.

The best way would be using transform: skew() for newer browsers.

But you need to keep in mind that this will transform every element inside that div as well. So the text inside your menu-bar would also come up skewed. To counter that, add a reverse-skew on the inner div like this:

.menu-container {
   ...
   transform: skewX(30deg);
   ...
}
.menu-inner {
   ...
   transform: skewX(-30deg);
   ...
}

Have fun experimenting... :)