function focusNaTab(tabName) {

    //alert(tabName);
    document.getElementById("tab_artilharia").style.backgroundImage = "url(/2009/Imagens/Estatisticas/art_qdo_" + tabName + "_sel.png)";
    document.getElementById("tab_classificacao").style.backgroundImage = "url(/2009/Imagens/Estatisticas/classif_qdo_" + tabName + "_sel.png)";
    document.getElementById("tab_estatisticas").style.backgroundImage = "url(/2009/Imagens/Estatisticas/estat_qdo_" + tabName + "_sel.png)";
    
    if (tabName != "art") {
        document.getElementById("art_conteudo").style.visibility = "hidden";
    } 
    
    if (tabName != "classif") {
        document.getElementById("classif_conteudo").style.visibility = "hidden";
    } 
    
    if (tabName != "estat") {
        document.getElementById("estat_conteudo").style.visibility = "hidden";
    }

    document.getElementById(tabName + "_conteudo").style.visibility = "visible";
}