Question

I need to create a corner block with CSS & html5.

Can somebody help me? Thanks.

update:
first of all, it should be div. I have image on my site, this is screen:

Answer:

#triangle-down {
    width: 0;
    height: 0;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    border-top: 100px solid red;
}

Answer 1

Are you looking to make a triangular div show up under your rectangular div? If so see this jsFiddle.

The CSS:

.triangle {
        width: 0;
        height: 0;
        border-left: 100px solid transparent;
        border-right: 100px solid transparent;
        border-top: 40px solid #999;
}

The HTML:

<div class="triangle"></div>