Verify that the Column has a Blank or Empty value

Good morning. I'm trying to verify that the column of a Parent-Child table has gone blank. Can anyone help me?

// VERIFICA SE ALGUM COLUNA FICOU EM BRANCO
var elVlr = $('#itensInventario tbody > tr > td input.linhaItemInventario');
$.each(elVlr, function(i, el) {
    if ($("#tb_NEX").val() == null || $("#tb_NEX").val() == "") {
    Status = "erro";
    }
});