Is there a way to pass multiple arrays to PHP json_encode and parse it with jQuery?

Question

Right now I have this PHP:

$columns = array(*/Data*/);
echo json_encode($columns);

And this is sent through an AJAX GET request with JQuery

Answer 1

After you have populated all the arrays namely $array1_json, $array2_json etc in my case,

$number_of_array1elements = count($array1_json);
$number_of_array2elements = count($array2_json);
$number_of_array3elements = count($array3_json);

array_unshift($array1_json , $number_of_array1elements); 
// pushes element to the start of array1_json
array_unshift($array2_json , $number_of_array2elements);
array_unshift($array3_json , $number_of_array3elements);

and similarly for other arrays.

echo json_encode( array_merge($array1_json, $array2_json, $array3_json) );

In your .js file, use:

var val = xmlhttp.responseText;
var jsonData = JSON.parse(val);
var number_of_array1elements = jsonData[0];
for (var i = 1; i <= number_of_array1elements; i++ ) 
{
    // use jsonData[i] to select the required element and do whatever is needed with it
}
var number_of_array2elements = jsonData[i];
for ( i = i+1; i <= number_of_array1elements+number_of_array2elements+1; i++ ) 
{
     // use jsonData[i] to select the required element and do whatever is needed with it
}