function checktype() {
  type = document.UPLOAD.n_Type.value;
  if(type=="Skin" | type=="ModMan") {
     MM_showHideLayers('case_skin','','show');
     show_skin();
     }else{
     MM_showHideLayers('case_skin','','hide');
     }
}

function show_skin() {
var select_categorie = document.UPLOAD.n_Categorie;
var selected_categorie = select_categorie.selectedIndex;
var select_skin = document.UPLOAD.n_Skin;
var selected_skin = select_skin.selectedIndex;
//alert(selected_skin);
if( typeof(cat[selected_categorie]) != "undefined" ) {
    nb_opt = cat[selected_categorie].length
    document.UPLOAD.n_Skin.options.length = 0; // efface le selectbox actuel
    for(var i=0; i<nb_opt; i++) {
       var val = cat[selected_categorie][i];
       document.UPLOAD.n_Skin.options[i] = new Option(val,val);
       }
    document.UPLOAD.n_Skin.selectedIndex = selected_skin;

    if(document.UPLOAD.n_Type.value=="Skin" | document.UPLOAD.n_Type.value=="ModMan") {MM_showHideLayers('case_skin','','show');}else{MM_showHideLayers('case_skin','','hide');}
    }else{
    MM_showHideLayers('case_skin','','hide');
    }
}