function selection_champs(champs,champs_affiche){
   //on récupère l'endroit sélectionner dans le select source
    selection = champs.selectedIndex;
    if(selection != -1){
        //on déselectionne tous les champs du select de destination où va être placer le(s) champ(s) selectionner
        while(champs_affiche.selectedIndex != -1){
            champs_affiche.options[champs_affiche.selectedIndex].selected = false;
        }

        while(champs.selectedIndex > -1){
            if(champs.options[champs.selectedIndex].value == "Id_type_bien"){
                champs.options[champs.selectedIndex] = null;
                champs.form.Id_categorie_bien.options[0].select= true;
            }else{
                //on cherche la place de notre champ
                for(place=0;place<champs_affiche.length;place++){
                    if(champs_affiche.options[place].text > champs.options[champs.selectedIndex].text){
                        break;
                    }
                }
                //on décale tous les champs
                for(i=champs_affiche.length;i>place;i--){
                    champs_affiche.options[i] = new Option(champs_affiche.options[(i-1)].text,champs_affiche.options[(i-1)].value);
                }

                //on insère le champ selectionner
                champs_affiche.options[place] = new Option(champs.options[champs.selectedIndex].text,champs.options[champs.selectedIndex].value);
                champs.options[champs.selectedIndex] = null;
                champs_affiche.options[place].selected = true;
            }
        }

        if(champs.length > 0){
            if(selection >= champs.length ){
                selection = champs.length-1;
            }
            champs.options[selection].selected = true;
        }
    }	
}

function select_all(selection){

    for(i=0;i<selection.length;i++){
        selection.options[i].selected = true;
    }
    selection.name = selection.name + '[]';
}

function priorite_champ(selection,mode){
    if(selection.length < 2 ){
		return;
		}
    old_place = selection.selectedIndex;
    if(mode == 'up' && old_place > 0){
        new_place = old_place-1;
    }else if(mode == 'down' && old_place < selection.length-1){
        new_place = old_place+1;
    }
    
    tmp = new Option(selection.options[new_place].text,selection.options[new_place].value);
    selection.options[new_place] = new Option(selection.options[old_place].text,selection.options[old_place].value);
    selection.options[old_place] = new Option(tmp.text,tmp.value);
    selection.options[new_place].selected = true;

}