<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"><head>
<style type="text/css">
#fleche {
display:block; float:left;
overflow:hidden; /* pout IE */
height:0px; width:0px;
border-top:8px solid #fff;
border-bottom:8px solid #fff;
border-left:8px solid red;
}
</style>
</head>
<body>
<span id="fleche"></span>Flèche/triangle en CSS
</body></html>