Ajax form return variables to php - php

Question

I have another question:
Ajax Forms are working well. Most of them need to do mysql stuff and only return values if the entry could be written or not. I used just echo statements. For example echo "1"; if the values could be written and echo "2"; if the values could not be written.
Now I need to call back 3 variables. I know that I can write them in an array. My problem is just, that I can't return this variable into my visible site.
This is my JavaScript Code:
//Show statistic
$('.statistic_submit').click(function(){
if ($('#month').val() == 'none' || $('#year').val() == 'none') {
$("#dialog_empty").dialog( "open" );
return false;
}
var form = $('#statistic_view');
var data = form.serialize();
$.ajax({
url: "include/scripts/user_statistic.php",
type: "POST",
data: data,
success: function (reqCode) {
if (reqCode == 1) {
//Show generated table
$('.done').fadeOut('slow');
$('.done').fadeIn('slow');
}
if (reqCode == 2) {
//No values found
$('.done').fadeOut('slow');
$("#dialog_error").dialog( "open" );
}
}
});
return false;
});
This is my html code:
<div>
<form id="statistic_view" action="include/scripts/user_statistic.php" method="post">
<select name="month" id="month">
<option value="none" class="bold italic">Monat</option>
<?php
for($i=1; $i<=12; $i++){
if($i == $month)
echo "<option value=\"".$i."\" selected>".$month_name[$i]."</option>\n";
else
echo "<option value=\"".$i."\">".$month_name[$i]."</option>\n";
}
?>
</select>
<select name="year" id="year">
<option value="none" class="bold italic">Jahr</option>
<?php
for($i=2012; $i<=$year; $i++){
if($i == $year)
echo "<option value=\"".$i."\" selected>".$i."</option>\n";
else
echo "<option value=\"".$i."\">".$i."</option>\n";
}
?>
</select>
<br/><br/>
<div id="user_statistic">
<input type="submit" id="small" class="statistic_submit" value="Daten anzeigen">
</div>
</form>
<br />
<div class="done">
<p class="bold center"><?php echo "Besucher ".$month_name[$month]." ".$year; ?></p>
<canvas id="cvs" width="680" height="250">[No canvas support]</canvas>
<script>
chart = new RGraph.Line('cvs', <?php print($data_string) ?>);
chart.Set('chart.tooltips', <?php print($labels_tooltip) ?>);
chart.Set('chart.tooltips.effect', 'expand');
chart.Set('chart.background.grid.autofit', true);
chart.Set('chart.gutter.left', 35);
chart.Set('chart.gutter.right', 5);
chart.Set('chart.hmargin', 10);
chart.Set('chart.tickmarks', 'circle');
chart.Set('chart.labels', <?php print($labels_string) ?>);
chart.Draw();
</script>
</div>
</div>
And this my user_statistic.php:
... (mysql stuff)
/******************************/
/** Create diagram
/******************************/
$labels = array();
$data = array();
for ($j=1; $j<=$days; $j++) {
$labels[$j] =$j;
$data[$j] = $day_value[$j];
}
// Aggregate all the data into one string
$data_string = "[" . join(", ", $data) . "]";
$labels_string = "['" . join("', '", $labels) . "']";
$labels_tooltip = "['" . join("', '", $data) . "']";
//data written
echo "1";
So echo "1"; tells my script that everything is fine. But now I need $data_string, $labels_string and $labels_tooltip. So how can I return these values from user_statistic.php into my side?

Answer 1

Avoid converting arrays to strings on your own. If you need to pass a PHP array back to your jQuery, you should do so with the json_encode function:
echo json_encode( $array );
This will come through as a JSON object which you can then handle client-side. Your JSON string will be returned into the callback of your $.ajax method:
$.ajax({
url: "include/scripts/user_statistic.php",
type: "POST",
data: data,
dataType: 'json',
success: function ( response ) {
/* response is your array, in JSON form */
}
});
For instance, if our PHP script did the following:
$response = array(
'message' => 'Success',
'allData' => array( 'Jonathan', 'Mariah', 'Samuel', 'Sally' )
);
echo json_encode( $response );
We could alert the message from our jQuery like this:
success: function ( response ) {
alert( response.message );
}

Answer 2

The best approach here would be to return a json object. Create an array on server side -
$response['error_code'] = '1'; //everything ok. 0 if not ok
$response['data_string'] = 'this will have some data';
$response['labels_string'] = 'labels';
$response['labels_tooltip' = 'here goes the tooltips';
echo json_encode($response);
and in your javascript code, mention the return datatype as json -
$.ajax({
url: "include/scripts/user_statistic.php",
type: "POST",
data: data,
dataType: json,
success: function (reqCode) {
if (reqCode.error_code == 1) {
alert('this is the data string '+resCode.data_string);
//Show generated table
$('.done').fadeOut('slow');
$('.done').fadeIn('slow');
}
if (reqCode.error_code == 2) {
//No values found
$('.done').fadeOut('slow');
$("#dialog_error").dialog( "open" );
}
}
});