Buongiorno,
ti posto il codice della pagina che si occupa di inserire la commessa di lavoro, io se provo a digitare anche per 15 volte il tasto shift+tab non compare l'alert, anche se per l'utente la cosa più semplice sarebbe quella di usare solo il tasto tab e quando arriva alla fine di ogni riga con il tab viene simulato il click sul pulsante (+)
<script type="text/javascript" src="js/validate.js"></script>
<?php include("js/cavicchi.js"); ?>
<form class="form" name="inscomm" method="post" id="modulo" action="index.php?page=salva_commessa" enctype="multipart/form-data">
<div class="form-container">
<div class="card-commesse">
<div class="card-header">Anagrafica Cliente</div>
<div class="card-block">
<div class="row">
<div class="col-md-2">
<div class="input-group">
<span class="input-group-addon"><i class="far fa-calendar-alt" aria-hidden="true"></i></span>
<input type="text" class="form-control" id="datepicker" placeholder="Data Commessa" name="data" autocomplete="off" required>
</div>
</div>
</div>
<hr>
<div class="row">
<div class="col-md-4">
<div class="input-group">
<span class="input-group-addon"><i class="fa fa-user" aria-hidden="true"></i></span>
<input type="text" class="form-control" aria-hidden="true" name="cliente" placeholder="Nome Cognome Cliente" required>
</div>
</div>
<div class="col-md-4">
<div class="input-group">
<span class="input-group-addon"><i class="fas fa-map-marker-alt" aria-hidden="true"></i></span>
<input type="text" class="form-control" name="indirizzo" placeholder="Indirizzo">
</div>
</div>
<div class="col-md-4">
<div class="input-group">
<span class="input-group-addon"><i class="fa fa-phone" aria-hidden="true"></i></span>
<input type="text" class="form-control" name="tel" placeholder="Telefono" required>
</div>
</div>
</div>
</div>
</div> <!--Close Div Anagrafica Cliente-->
<div class="card-commesse">
<div class="card-header">Anagrafica Vettura</div>
<div class="card-block">
<div class="row">
<div class="col-md-4">
<label class="sr-only" for="Veicolo">Veicolo</label>
<div class="input-group mb-2 mr-sm-2 mb-sm-0">
<span class="input-group-addon"><i class="fa fa-car" aria-hidden="true"></i></span>
<input type="text" class="form-control" name="veicolo" placeholder="Veicolo" required >
</div>
</div>
<div class="col-md-4">
<label class="sr-only" for="Targa">Targa</label>
<div class="input-group mb-2 mr-sm-2 mb-sm-0">
<span class="input-group-addon"><i class="fa fa-hand-o-right" aria-hidden="true"></i></span>
<input type="text" class="form-control" name="targa" placeholder="Targa Veicolo" id="targa" maxlength="8" onkeyup="VerificaTarga(this)" required>
</div>
</div>
<div class="col-md-4">
<label class="sr-only" for="Km">Km</label>
<div class="input-group mb-2 mr-sm-2 mb-sm-0">
<span class="input-group-addon"><i class="fa fa-refresh" aria-hidden="true"></i></span>
<input type="text" class="form-control" name="km" placeholder= "Km Veicolo" id="km" onkeyup="VerificaKm(this)" required>
</div>
</div>
</div>
<hr>
<div class="row">
<div class="col-md-4">
<label class="sr-only" for="n_tecnico">Tecnico</label>
<div class="input-group mb-2 mr-sm-2 mb-sm-0">
<span class="input-group-addon"><i class="fa fa-users" aria-hidden="true"></i></span>
<select class="form-control" id="n_tecnico" name="n_tecnico" required>
<?php
$sq1 = "SELECT * FROM tecnico ORDER BY n_tecnico ASC";
$rs1 = $mysqli->query($sq1);
echo "<option value=''> Seleziona Tecnico ... </option>";
while ($row = $rs1->fetch_array(MYSQLI_ASSOC)) {
$n_tecnico = mysqli_real_escape_string($mysqli, strtoupper($row['n_tecnico']));
echo "<option value='$n_tecnico'>$n_tecnico</option>";
}
?>
</select>
</div>
</div>
<div class="col-md-4">
<label class="sr-only" for="pagamento">Pagamento</label>
<div class="input-group mb-2 mr-sm-2 mb-sm-0">
<span class="input-group-addon"><i class="fa fa-credit-card" aria-hidden="true"></i></span>
<select class="form-control" id="pagamento" name="pagamento" required>
<?php
$sq1 = "SELECT * FROM tipo_pagamento ORDER BY stato_pag ASC";
$rs1 = $mysqli->query($sq1);
echo "<option value=''> Seleziona Pagamento </option>";
while ($row = $rs1->fetch_array(MYSQLI_ASSOC)) {
$stato_pag = mysqli_real_escape_string($mysqli, strtoupper($row['stato_pag']));
echo "<option value='$stato_pag'>$stato_pag</option>";
}
?>
</select>
</div>
</div>
<div class="col-md-4">
<label class="sr-only" for="allegato">Allegato</label>
<div class="input-group mb-2 mr-sm-2 mb-sm-0">
<span class="input-group-addon"><i class="fa fa-paperclip" aria-hidden="true"></i></span>
<select class="form-control" id="allegato" name="allegato" required>
<?php
$sq1 = "SELECT * FROM allegato ORDER BY allegato ASC";
$rs1 = $mysqli->query($sq1);
echo "<option value=''> Allegato </option>";
while ($row = $rs1->fetch_array(MYSQLI_ASSOC)) {
$allegato = mysqli_real_escape_string($mysqli, strtoupper($row['allegato']));
echo "<option value='$allegato'>$allegato</option>";
}
?>
</select>
</div>
</div>
</div>
</div>
</div><!--Close Div Anagrafica Vettura-->
<div class="card-commesse">
<div class="card-header">Interventi Manutenzione Veicolo</div>
<div class="card-block">
<table id="commessa">
<tbody>
<tr>
<td>Intervento</td>
<td>Fornitore</td>
<td>Q.tà</td>
<td>Unitario</td>
<td>Sconto %</td>
<td>Totale</td>
<td>Aggiungi</td>
</tr>
<tr class="righe">
<td><input type="text" name="itr1" id="itr1" class="t1" size="30" placeholder="Max 49 caratteri" maxlength="49" required ></td>
<td><input type="text" name="for1" id="for1" class="t1" size="10"></td>
<td><input type="text" name="q1" class="t2 somma" onKeyUp="SommaRiga(1)" id="q1" size="3" value="0.0" placeholder="0" required></td>
<td><input type="text" name="iu1" class="t2 somma" onKeyUp="SommaRiga(1)" onBlur="Format(1)" id="iu1" size="6" value="0.0" placeholder="0.00" autocomplete="off"></td>
<td><input type="text" name="sc1" class="t2 somma" onKeyUp="Virgola(1)" id="sc1" size="8" value="0.0" placeholder="sconto" autocomplete="off"></td>
<td><input type="text" name="imp_1" id="imp_1" class="t2 somma" size="8" value="0.0" placeholder="0.00" readonly></td>
<td><img src="images/add.png" name="add1" width="16" height="16" id="add1" class="add"></td>
</tr>
<tr>
<td></td>
<td></td>
<td></td>
<td></td>
<td>Tot. Gen.</td>
<td><input type="text" name="totale" class="t2" id="totale" size="7" value="" placeholder="0.00" readonly></td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="card-commesse">
<div class="card-header">Gestione Allegati</div>
<div class="card-block">
<div class="row">
<div class="col-md-4">
<label class="control-label">Allegato 1</label>
<input id="allegato1" name="allegato1" type="file" class="file file-loading" data-allowed-file-extensions='["pdf", "xls", "xlsx", "doc", "docx" ]'>
</div>
<div class="col-md-4">
<label class="control-label">Allegato 2</label>
<input id="allegato2" name="allegato2" type="file" class="file file-loading" data-allowed-file-extensions='["pdf", "xls", "xlsx", "doc", "docx" ]'>
</div>
<div class="col-md-4">
<label class="control-label">Allegato 3</label>
<input id="allegato3" name="allegato3" type="file" class="file file-loading" data-allowed-file-extensions='["pdf", "xls", "xlsx", "doc", "docx" ]'>
</div>
</div>
</div>
</div><!--Close Div Gestione Allegati-->
<div class="text-right">
<button type="submit" class="btn btn-success right" onclick="return confirm('Vuoi registrare la commessa ?')">Registra commessa</button>
</div>
</div><!--Close Form Container-->
</form><!--Close Form-->