current community

your communities

more stack exchange communities

Stack Exchange
tour help
careers 2.0
Take the 2-minute tour ×
Stack Overflow is a question and answer site for professional and enthusiast programmers. It's 100% free, no registration required.
up vote 0 down vote favorite

I am having trouble trying to return results from a PHP script, back into my HTML / Jquery application.

Currently, I am trying to connect to the server like so:

function getDatabaseRows()
{           
    var xmlHttp = new XMLHttpRequest();

    xmlHttp.onreadystatechange = function()
    {
        if(xmlHttp.readyState == 4)
        {
          HandleResponse(xmlHttp.responseText);
        }
    }

    xmlHttp.open("POST", "myDomain.com/subDirectory/getRowCounts.php", true);
    xmlHttp.send(null);
}

With my response handler being:

function HandleResponse(response)
{   
    alert(response.length);

    if(response.length != 0)
        maxArray = JSON.parse(response);

    storage.set('currentID', maxArray);
}

Currently, whenever I run the code, getDatabaseRows() always ends up calling HandleResponse(response). The problem is that response.length always equals 0.

The PHP script is simply collecting the maximum row count from the database and returning the row counts:

<?php

   $rowCounts = [];

   $dbhost = 'host';
   $dbuser = 'host';
   $dbpass = 'host';

   $con = mysql_connect($dbhost, $dbuser, $dbpass) or die('Error connecting to mysql');
   mysql_select_db("host") or die(mysql_error());

   $sql = "SELECT MAX(TID) AS MaxTID FROM TransData";
   $results = mysql_query($sql, $con);
   $transRow = mysql_fetch_array($results);
   $maxTrans = $transRow['MaxTID'];

   $sql = "SELECT MAX(FID) AS MaxFID FROM FullData";
   $results = mysql_query($sql, $con);
   $fullRow = mysql_fetch_array($results);
   $maxFull = $fullRow['MaxFID'];

   $sql = "SELECT MAX(SID) AS MaxSID FROM SalamanderData";
   $results = mysql_query($sql, $con);
   $salamanderRow = mysql_fetch_array($results);
   $maxSal = $salamanderRow['MaxSID'];

   $sql = "SELECT MAX(OID) AS MaxOID FROM OthersData";
   $results = mysql_query($sql, $con);
   $othersRow = mysql_fetch_array($results);
   $maxOther = $othersRow['MaxOID'];

   array_push($rowCounts, $maxTrans, $maxFull, $maxSal, $maxOther);

   echo json_encode($rowCounts);

   mysql_close($con);
?>

When I point my browser directly to the script, it echo's the row counts correctly for me. I am only having trouble trying to get data through AJAX.

EDIT:

Ok, I finally got the script connected, it had something to do with Cross-Domain scripting problems. All sorted out now.

New problem though:

function HandleResponse(response)
{   

    if(response.length != 0)
        maxArray = JSON.parse(response);

    storage.set('currentID', maxArray);
}

HandleResponse throws an error when parsing the JSON Error trying to parse '<', So I assume that it has something to do with the way that Array was encoded. How do I go about troubleshooting this problem and figuring out how to parse that array?

share|improve this question

2 Answers 2

up vote 0 down vote

I would check out the following connection method.

http://api.jquery.com/jQuery.get/

This will solve all your issues and clean up your code

This is a sample of one of my old codes

    $.ajax({
        data: "id=" + value,
        type: "POST",
        url: "unlock.php",
        success: function (data) {
            if (data == 1 || data == true) {
                var result = true;
            } else {
                var result = false;
            }
        }
    });
share|improve this answer
    
api.jquery.com/jQuery.get - "load data from the server using a HTTP GET request." I think he's using POST. –  samura Sep 12 '12 at 20:09
2  
yeah...writing your own javascript ajax calls is masochistic –  Matt Whipple Sep 12 '12 at 20:10
    
you talk about jQuery.get then you use $.ajax –  samura Sep 12 '12 at 20:11
    
@samura He isn't sending any POST data, so a GET is equivalent. –  Samuel Sep 12 '12 at 20:11
    
@Samuel true. it could be done with GET. –  samura Sep 12 '12 at 20:12
up vote 0 down vote

This is the simplest jQuery JavaScript I could get it down to (this uses the GET method):

function getDatabaseRows()
{           
  $.getJSON('myDomain.com/subDirectory/getRowCounts.php', function(data) {
    console.log(data);
  });
}

Documentation at http://api.jquery.com/jQuery.getJSON/

And some enhancements to your PHP using a foreach {} and mysql_result(), although you may want to look into PHP's mysqli class for a more future-proof solution.

$rowCounts = array();

$dbhost = 'host';
$dbuser = 'host';
$dbpass = 'host';
$dbase  = 'host';

$fields = array(
    'MaxTID' => array('tab' => 'TransData',      'col' => 'TID'),
    'MaxSID' => array('tab' => 'FullData',       'col' => 'SID'),
    'MaxFID' => array('tab' => 'SalamanderData', 'col' => 'FID'),
    'MaxOID' => array('tab' => 'OthersData',     'col' => 'OID')
  );

$con = mysql_connect($dbhost, $dbuser, $dbpass) or die('Error connecting to mysql');
mysql_select_db($dbase, $con) or die(mysql_error());

foreach ($fields as $id => $info) {
  $sql = "SELECT MAX({$info['col']}) FROM {$info['tab']}";
  $result = mysql_query($sql, $con);
  if (!$result) die('Could not query:' . mysql_error());
  $rowCounts[$id] = mysql_result($result, 0);
}

echo json_encode($rowCounts);

mysql_close($con);

This code worked on a GoDaddy hosted site. For the record, this is my first Stack Overflow answer. Please advise :)

share|improve this answer
    
If you need to use POST $.ajax( {url: 'myDomain.com/subDirectory/getRowCounts.php', type: "POST", dataType: 'json', success: function(data) { console.log(data); } } ); will do the same thing as above, but with POST instead of GET. –  Matt Janssen Sep 12 '12 at 21:36
    
Obviously don't forget your <script src="http://code.jquery.com/jquery-latest.js"></script> in the <head>. –  Matt Janssen Sep 13 '12 at 5:20
    
Check my Edit on the question –  Brendan Sep 13 '12 at 18:32
    
@Brendan Can you show me the data string that's being spit back by getRowCounts.php? For example, my test script returns ["63184","134187","186314"]. I'm getting no such problems in HandleResponse() when testing your code. Could there be a problem with the storage.set() call? –  Matt Janssen Sep 14 '12 at 4:41
1  
Glad you figured it out! –  Matt Janssen Sep 15 '12 at 5:41

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.