Making jagged triangle border in CSS - css

Question

I have a shape with an edge like this in Photoshop:
Is it possible to make the repeated triangles as a border with CSS?

Answer 1

You can use gradients to create a zig-zag patterned background, use the ::after pseud-element to apply it like a border.
.header{
color: white;
background-color: #2B3A48;
text-align: center;
}
.header::after {
content: " ";
display: block;
position: relative;
top: 0px;
left: 0px;
width: 100%;
height: 36px;
background: linear-gradient(#2B3A48 0%, transparent 0%), linear-gradient(135deg, #272220 33.33%, transparent 33.33%) 0 0%, #272220 linear-gradient(45deg, #272220 33.33%, #2B3A48 33.33%) 0 0%;
background-repeat: repeat-x;
background-size: 0px 100%, 9px 27px, 9px 27px;
}
<div class="header"><h1>This is a header</h1></div>
Source: CSS Zigzag Border with a Textured Background
JSFiddle: http://jsfiddle.net/kA4zK/

Answer 2

For future viewers, I found this adaptation of #extramaster's answer to be a little simpler.
It's essentially the same, but it uses one fewer background gradients and allows the backing object (.navbar in my markup) to show through instead of hard-coding the second color into the zig-zag.
JsFiddle: http://jsfiddle.net/861gjx0b/2/
.header {
position: relative;
color: white;
background-color: #2B3A48;
text-align: center;
}
.navbar {
background: #272220;
height: 20px;
}
.header:after {
content: "";
position: absolute;
display: block;
height: 10px;
bottom: -10px;
/* -height */
left: 0;
right: 0;
/* TODO Add browser prefixes */
background: linear-gradient( 45deg, transparent 33.333%, #2B3A48 33.333%, #2B3A48 66.667%, transparent 66.667%), linear-gradient( -45deg, transparent 33.333%, #2B3A48 33.333%, #2B3A48 66.667%, transparent 66.667%);
background-size: 8px 20px;
/* toothSize doubleHeight */
background-position: 0 -10px;
/* horizontalOffset -height */
}
<div class="header">
<h1>This is a header</h1>
</div>
<nav class="navbar"></nav>

Answer 3

Personally, I think clip-path is easier to work with/understand than complex background gradients.
body {
font-family:Roboto,'Open Sans',Helvetica,sans-serif;
}
.container {
background:#ddd;
margin:0 auto;
max-width:800px;
padding:30px;
}
h1:first-child {margin:0;}
.jagged-bottom {
position:relative;
}
.jagged-bottom:after {
background:#ddd;
content:"";
height:2vw;
position:absolute;
top:100%;
left:0;
right:0;
clip-path:polygon(
0 0, 2.5% 100%, 5% 0, 7.5% 100%,
10% 0,12.5% 100%,15% 0, 17.5% 100%,
20% 0,22.5% 100%,25% 0, 27.5% 100%,
30% 0,32.5% 100%,35% 0, 37.5% 100%,
40% 0,42.5% 100%,45% 0, 47.5% 100%,
50% 0,52.5% 100%,55% 0, 57.5% 100%,
60% 0,62.5% 100%,65% 0, 67.5% 100%,
70% 0,72.5% 100%,75% 0, 77.5% 100%,
80% 0,82.5% 100%,85% 0, 87.5% 100%,
90% 0,92.5% 100%,95% 0, 97.5% 100%, 100% 0);
}
<div class="container jagged-bottom">
<h1>Looks Like A Receipt</h1>
<p>Simply adjust the clip path on the pseudo-element if you want more or fewer spikes, and the height if you want them to be taller or shorter.</p>
</div>

Answer 4

There is a border-image property in CSS3.
Maybe you can work it out in a way you want. More here:
https://developer.mozilla.org/en-US/docs/Web/CSS/border-image
Or here
https://www.w3schools.com/cssref/css3_pr_border-image.asp

Answer 5

You can create an individual triangle using CSS quite easily (just tweak border properties). In order for this to work you will need to generate quite a bit of markup yourself. I would recommend against this approach.
Instead you are likely better off using an individual image containing a single triangle (preferably a transparent .png) and then use background-image and background-repeat (repeat-x) properties to bind that to a div (your "border").
Unfortunately there is no yet a straight-forward way to achieve this using pure CSS.