function keyPressed(event) {
    if (event.keyCode == '13') {
        BuscaMapa();
    }
}

function BuscaMapa() {
    var Origem;
    if (document.getElementById("txtCepCidade").value != '') {
        var Origem = document.getElementById("txtCepCidade").value;
        document.getElementById("mapaPadrao").style.display = "none";
        document.getElementById("mapaPadrao").style.height = "0px";
    }
    document.getElementById("frmMapa").style.height = "0px";
    document.getElementById("imgLoading").style.display = "block";
    document.getElementById("frmMapa").src = "Localizacao_Mapa.aspx?Origem=" + Origem;
    return false;
}