var grid = new Grid({
    store: store,columns: [
        { id: "artist",label: "Artist",field: "Artist"},{ id: "name",label: "Song",field: "Name"},{ id: "gerne",label: "Genre",field: "Genre"}
    ]
},"grid-placeholder");

// to hide column with id="name"
grid.styleColumn("name","display: none;");

// to show it
grid.styleColumn("name","display: table-cell;");