Edit in JSFiddle

<div id="boardDiv"></div>
<div style="margin-top:20px;">
    <div>Introduce Notación FEN</div>
    <div><textarea id="txtFEN" style="width:600px;height:100px;">5r1k/3b2p1/p6p/1pRpR3/1P1P4/P4pPq/5Qn1/1B4K1 w - - 0 1</textarea></div>
    <div><input id="iActualizar" type="button" value="Actualiza" onclick="CargarFen();" /></div>
    <div style="margin:10px 0px;border:dotted 1px black;padding:10px;">
        <div>Algunos FEN</div>
        <div>rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1</div>
        <div>rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR w KQkq c6 0 2</div>
        <div>rnbqkbnr/pp1ppppp/8/2p5/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2</div>            
    </div>
</div>

var chessObj;
$(document).ready(
    function()
    {
        CargarFen();
    }
);
function CargarFen()
{
    chessObj = new DHTMLGoodies.ChessFen({ pieceType: 'alpha',squareSize:45 }); 
    //merida, smart, motif, cases, leipzig
    chessObj.loadFen($.trim($("#txtFEN").val()), 'boardDiv');            
}