如何在javascript中进行基于下拉的查询mysql？ [重复]

<script type="text/javascript">
var rowNum = 0;
function addRow(frm) {
    rowNum ++;
    var row = '<p id="rowNum'+rowNum+'"> Barang: ';
    row += '<select name="???">';
    row += '<option value="A1">A1</option>';
    row += '<option value="A2">A2</option>';
    row += '<option value="A3">A3</option>';
    row += '<option value="A4">A4</option>';
    row += '</select>';
    row += ' Satuan: <input type="text" size="5" name="satuan[]" value="'+frm.add_satuan.value+'"> Quantity: <input type="text" name="qty[]" value="'+frm.add_qty.value+'"> <input type="button" value="Remove" onclick="removeRow('+rowNum+');"><hr color=red></p>';

    $('#itemRows').append($(row));
     frm.add_qty.value = '';
     frm.add_nama.value = '';
         frm.add_satuan.value = '';
};
  </script>

How to make drop-down list but with query mysql to show A1, A2, dll. When submit button for drop-down can't post data anything. Can I store data with this javascript. For text input success post data.

</div>

DO NOT DO WHAT YOU ARE TRYING TO DO. You should never, ever, ever write queries on the front-end. You should do your absolute best to hide every detail of the server/database from the user. It is a massive security risk. Please read about SQL injection attacks for starters.

How you should do this:

Store the values of the dropsdowns in JavaScript. Let's keep them in a single object to make life easy:

Your JS:

var options = {
  A1: $("#rowNum select option[value='A1']").text(),
  A2: $("#rowNum select option[value='A2']").text(),
  A3: $("#rowNum select option[value='A3']").text(),
  A4: $("#rowNum select option[value='A4']").text()
};

// Now, send this object to your PHP via an AJAX call. Let's assume for simplicity that you will do this using jQuery:
$.ajax({
  url: 'my/php/script.php',
  data: options,
  success: function (data) { console.log('Yay, it worked!'); },
  error: function (jqXHR, textStatus, error) { console.log('crap it didn't work', jqXHR, textStatus, error); }
});

Your PHP

<?php

$options = $_REQUEST['options']
// You need to verify the options are valid (and don't have bad values) but that's a different question

// Build your query here. Your PHP is run on the server only so no one else will see it or be able to change it.

You can try this code with some modification. Use jQuery's each to iterate over the array value.

$('#emptyDropdown').empty();
// Parse the returned json data
//var opts = $.parseJSON(data);//Remove comment if you are using JSON

// Use jQuery's each to iterate over the opts value
$.each(opts, function(i, d) {
    // You will need to alter the below to get the right values from your data.
    $('#emptyDropdown').append('<option value="' + d.yourID + '">' + d.yourValue + '</option>');
});