How to parse a SQL query return in javascript?

Question

I have tried looking at the related links and googled this, but I haven't found anything that can exactly help me. And excuse a web development newb here. This is probably a really easy answer:

What I'm doing is an ajax javascript function that calls a php file. This php file connects to the database and gets all the information from a table, like so:

<?php require_once('Connections/callConn.php'); ?>
<?php

$query_getStatus = "SELECT tStatus FROM tables";
$status = mysql_query($query_getStatus, $callConn) or die(mysql_error());
$row_status = mysql_fetch_assoc($status);
$tStatus = $row_status['tStatus'];

echo $tStatus;

mysql_close($con); 
?>

And then in my javascript function, I have a var equal to the xmlhttp.responseText. What I want to do is parse this so I can make an array out of it, then do a for loop with that array. But I'm honestly not sure how to do it. Like I said, likely very easy, I just can't find an example for this. Thanks!

consider looking at some JS framework.

joakimdahlstrom
– joakimdahlstrom

2012-02-29 00:39:36 +00:00
Commented Feb 29, 2012 at 0:39 — joakimdahlstrom
– joakimdahlstrom, Commented Feb 29, 2012 at 0:39

Mike B · Accepted Answer · 2012-02-29 00:21:12Z

3

You can print the response in php as JSON then eval it in javascript to access it like an array. Take a look at json_encode()

answered Feb 29, 2012 at 0:21

Mike B

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Timeout · Accepted Answer · 2012-02-29 01:05:32Z

2

Take your data from PHP and run it through json_encode (as Mike B mentioned).

Then I would recommend switching to jQuery so that you can easily evaluate the JSON response from the JS side.

// Assuming a GET request.
$.get('your_page.php', 
      {}, 
      function(data) {
          // "data" is your JSON object.
      },
      "json");

(from the comments)

jQuery has already wrapped some preferred logic around evaluating JSON. It will first attempt to parse it using the browsers native json parser (if available). If that fails it will try to verify the json string and evaluate it using new Function as opposed to eval().

new Function will not affect local variables whereas eval() is allowed to mess with them since it executes the code in the current scope.

edited Feb 29, 2012 at 1:05

answered Feb 29, 2012 at 0:30

Timeout

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3 Comments

Mike B Over a year ago

afaik, to parse json into javascript variables is just eval()

Timeout Over a year ago

eval() is a bit quirky and slower. jQuery will attempt to use the browsers native JSON parser first. Then it will do a sanity check on the text before a "new Function", not eval directly.

fvertk Over a year ago

Thanks! I liked this answer since it was a bit more detailed, but both were good. Still don't understand completely what they are parsing in/out, but it works!

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