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I have PHP function inside a class that returns a math problem:

public function level1() {

    //level 1 and 2
    //single digit addition and subtraction
    //randomly choose addition or subtraction
    //1 = addtion, 2 - subtraction
    $opperand = rand( 1, 2 );

    //if the problem is a subtraction, the program will keep generating problems if a negative problem is generated
    //if opperand is a subtraction, do generate both numbers while the answer is negative

    if ( $opperand == 2 )
        {
        do {

            //randomly generate first number
            $number1 = rand( 1, 9 );

            //randomly generate second number
            $number2 = rand( 1, 9 );

            //compute the answer
            $answer = $number1 - $number2;

            //change variable to actual opperand
            $opperand = "-";
        } while ( $answer < 0 );
        }
    else
        {//addition problem
        //randomly generate first number
        $number1 = rand( 1, 9 );

        //randomly generate second number
        $number2 = rand( 1, 9 );

        //compute the answer

        $answer = $number1 + $number2;

        //change variable to actual opperand
        $opperand = "+";
        }//end if/else

    return array( $number1 . " " . $opperand . " " . $number2 . " ", $answer );

I call this function from ajaxHandler.php (Which I call from ajax)

   $problemData = $MathEngine->level1();
    return $problemData;

The php will always return an array, but I cannot figure out how to manipulate or even view the results as an array in javascript. Is there a way to do this? I've used the standard Get ajax call before so that's not new. when I try to reference the ajax response text as an array, I either get nothing (when i click the button) or 'undefined'

           var problemData = ajaxRequest.responseText;

           alert( problemData[0] )
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2  
Have a look for JSON –  Geert Jaminon Nov 21 '12 at 22:11
 
would you be able to link to an in-depth tutorial? –  KiloJKilo Nov 21 '12 at 22:12
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4 Answers

up vote 2 down vote accepted 
// php - this will produce a json string
echo json_encode(array( $number1 . " " . $opperand . " " . $number2 . " ", $answer ));

// and in javascript - parse json string to javascript object
var problemData = JSON.parse(ajaxRequest.responseText);
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do i echo or return the json_encode inside the ajaxHandler.php –  KiloJKilo Nov 21 '12 at 22:29
 
Yes, you can. You must use an "echo", "print" or anything that returns a string. –  Tomasz Szuba Nov 22 '12 at 18:40
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up vote 1 down vote

try to echo $problemData; instead of returning it. what is the error when you call alert( problemData[0] )? ajax does only capture string or json objects so only way to do this is to return this array as string and splitting it in js or using json_encode on that array on php side

var data = problemData.split(' ');
alert(data[0]);
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I changed return to echo, it returns "<" no quotes –  KiloJKilo Nov 21 '12 at 22:23
 
It's weird, I get < in firefox and 'undefined' in IE. If I change it to [1], I get 'b' on firefox and 'undefined' on IE. i see your edits, i'm going to try it out –  KiloJKilo Nov 21 '12 at 22:27
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up vote 1 down vote

I'd use JSON. If you've never heard of JSON before, it's just an easy way to send content back and forth between languages / platforms.

In your PHP script, add this snippet to echo your array as JSON encoded text. The response to your AJAX request will be whatever you echo.

// End of PHP script
$problemData = $MathEngine->level1();
$tmpOut = '{"bind":'. json_encode(array("problemData" => $problemData)) .'}';
echo $tmpOut;
exit;

Now in your Javascipt, decode your JSON string.

// Javascript
var jsonObj=eval("("+ajaxRequest.responseText+")");
var problemData = jsonObj.bind.problemData;
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up vote 0 down vote

you can use json object to send and receive the data from javascript(AJAX) to php .use json_encode() to encode data from php and then pass it onto javascript in form of html or text . the javascript then calls json_decode to retrive the data and display.

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