Update JavaScript variables in background using PHP + jQuery

Question

This is a part of the code in a 'process.php' file:

echo "<script type='text/javascript'> percYes = ".$yes."</script>"
echo "<script type='text/javascript'> percNo = ".$no."</script>"

This 'process.php' file runs in the background (using jQuery/ajax) when the user clicks a butto. The 'echoed' html above replaces the contents of a div. So essentially what I'm trying to do is update some Javascript variables using a background php call, the above solution does not seem to work though, i.e. the script is not being ran once it is placed in the div.

A bonus problem involves using these updated Javascript variables to update a graph. I have a workng javascript graphing function, but the problem is getting the new graph to replace the old one (or just update it, if that's possible).

Thanks.

Answer 1

If all you are trying to do is update some JS vars, you may be better off having your process.php file returning a json string:

$array = ('percYes' => $yes, 'percNo' => $no);
echo json_encode($array);

This will give you a json string that can be evaluated and used in a callback for your JS ajax call.

So if you have a var 'percYes' and 'percNo' in an accessible scope, your callback could look something like this:

function(jsonstr) {
  obj = eval(jsonstr);
  percYes = obj.percYes;
  percNo  = obj.percNo;
}

I hope this helps.