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I have a php file that sends string to a js file using xmlhttp. The js file should convert the string to an object and start doing his thing on this object.

Well, the php file is printing this string:

$obj="{status:'ok',data:'{link:\"".$link."\",c:\"".$c."\",p:\"".$p."\"}'}";
echo $obj;

and the js file should get this:

{status:'ok',data:'{link:"http://test.com/test.html",c:"9",p:"1"}'}

While I'm trying to convert this string on the js file from string to an object, I'm getting a syntax error on ie8 (works fine in firefox and chrome).

Here is how I do it in the js file:

eval("var response=" + xmlhttp.responseText);

I tried to place the string manually in the js file and the eval worked, so I think the problem is with the apostrophes and quotation marks posted by the php file.

What do you think? does anyone knows a solution for this kind of problem?

Thanks in advance!

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1  
Have you checked what the expression "var response=" + xmlhttp.responseText actually evaluates to? –  Roy Tang Dec 13 '11 at 4:35
 
Hi Roy, here is what I get when I print it: var response={status:'ok',data:'{link:"http://test.com/test.html",c:"9",p:"1"}'}' –  Avi Levin Dec 13 '11 at 4:42
1  
Why don't you use PHP's JSON library to create a standard JSON string and then use a JSON library in JavaScript to load the object on the client, rather than using eval? –  Jordan Dec 13 '11 at 4:50
1  
Note that (whether it actually works or not) your sample is not valid JSON: the key names and values both have to be quoted with double quotes (your keys are not quoted and your values use single quotes - which would still be valid JS if you eval it, but still invalid JSON). –  nnnnnn Dec 13 '11 at 4:55
 
Yes, I know - but a valid JSON didn't work for the eval. –  Avi Levin Dec 13 '11 at 4:56
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2 Answers

up vote 2 down vote

To elaborate on my comment above, PHP and JavaScript both make it very easy to encode and decode JSON. Your PHP would look like this, a clean nested array with no ugly string concatenation:

<?php
$obj = array(
  'status' => 'ok',
  'data'   => array(
    'link' => $link,
    'c'    => $c,
    'p'    => $p
  )
);
?>

...and your JavaScript would look like this, no ugly eval:

<script>
  var response = JSON.parse(xmlhttp.responseText);
</script>

In the event you're using a copy of PHP without JSON support compiled in and aren't able to bring it up to date on your own, there are many open source JSON libraries for PHP you can drop in that have the same functionality, including Services_JSON from PEAR.

In the event you're stuck supporting browsers without JSON built in, just drop in json2.js.

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Hi Jordan, I tried using JSON.parse() from json2.js. It is cleaner, but the problem remains... I'm keep getting a syntax error in ie8 - this time it's pointing at json2.js file, line 472. You guessed right - at line 472 json2.js uses eval... So I'm back to the start... Any other ideas? Thanks again! –  Avi Levin Dec 14 '11 at 6:10
 
Hi again, I am really sorry for the trouble - I found that one of my php didn't send the JSON string correctly!! It's working now in both ways - eval and json2.js Many thanks for your kind help! :) –  Avi Levin Dec 14 '11 at 7:30
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I found that one of my php didn't send the JSON string correctly!! It's working now in both ways - eval and json2.js Many thanks for your kind help! :)

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