Question

EDITED:

SQL

$valuefromjs = $_REQUEST['var'];
$result6 = "SELECT DISTINCT $valuefromjs FROM persons ORDER BY $valuefromjs ASC";
$result7 = mysql_query($result6);
$num = mysql_num_rows($result7);  

$dataRanges[0] = array('dataRanges');       
        for ($i=1; $i<($num+1); $i++)
        {
        $dataRanges[$i] = array( (int) mysql_result($result7, $i-1) );
        }

echo json_encode($dataRanges);

HTML

<select id="combo2" class="combo" data-index="2"></select>

jQuery

$('#1combo').on('change', function () {
var jsonVar = $.ajax({
url : "visits/comboquery.php?var="+$(this).val(), 
dataType: "json",
async: false,
success: function(response) {
}
}).responseText;
for (var i=1; i<objVar.length;i++)
    {
    $('#combo2').html("<option value="+objVar[i]+">"+objVar[i]+"</option>");
    }
});

QUESTION:

I have an array with query results. Now i need that results be the combo2 options, what is wrong?

Answer 1

To my understanding the choice from combo1 will define which query to run for building combo2.

The issue: your PHP for building the combo2 is parsed at the server side i.e. the PHP code is always finished executing by the time the page reaches the user’s browser and your javascript begins to execute.

If you have a finite set of possible queries that can generate the seconds combo (which should be the case since combo1 has a finite number of options), you can create all of them, each with a different id, and maintain them hidden (css “display: none”).

<select id="firstCombo2" class="combo2">
    ...
</select>
<select id="secondCombo2" class="combo2">
    ...
</select>

etc.

Now, when the user makes a selection from combo1, you can decide which one of the hidden combo2’s you are going to display (css “display: block”).

$('select#combo1).on("change", function(){
    $('select.combo2').css('display','none'); //hide all combo2's
    if($(this).val()=='Opt1'){
            $('select#firstCombo2').css('display','block');
    }else if($(this).val()=='Opt2'){
            $('select#secondCombo2').css('display','block');
    }
}