Why my border-image didn't display in Firefox 15 — 09 Oct 2012

A quick CSS tip before I forget:

I've been wrecking my brains this afternoon to figure out why a border-image stopped displaying properly in the lastest version of Firefox (15.0.1) although it showed up properly in previous versions.

The CSS properties were:

div.mod-registration {
border-width: 164px 51px 98px 90px;
-moz-border-image: url(../img/torn-paper02.png) 164 51 98 90 stretch;
-webkit-border-image: url(../img/torn-paper02.png) 164 51 98 90 stretch;
-o-border-image: url(../img/torn-paper02.png) 164 51 98 90 stretch;
border-image: url(../img/torn-paper02.png) 164 51 98 90 stretch;
}

But nothing was displayed, as if border-image wasn't supported.

The trick was to specify a border-style:

border-style: solid;

Now everything is back to normal.