I have worked with JSON data, Jquery's getJSON method to use PHP's server side scripts to get data. Now I am trying to work with JSON data being returned by a PHP function and a Javascript event or url would get that data. For a Javascript function to access PHP data, it has to have a callback, and I am not able to figure out, how I should create a callback.
Existing code that I have in the PHP file (getData.php) can echo/return JSON output and would give data that would look like this
{"count":3,"items":[{"myTab_ID":"1","myTab_xam":"test1","myTab_rank":"21"},
{"myTab_ID":"2","myTab_xam":"test2","myTab_rank":"22"},
{"myTab_ID":"3","myTab_xam":"test3","myTab_rank":"22"}]}
Now I have my javascript file which would be making the call, which would be a little twitter like,
<html>
<head>
<script type="text/javascript" src="http://myserver/getdata.php">
</script>
</head>
</html>
Now when I run this html file, I get an error saying
"Error: invalid label Source File: http://myserver/getData.php Line: 1, Column: 1 Source Code: {"count":3,"items":[{"myTab_ID":"1","myTab_xam":"test1","myTab_rank":"21"},{"myTab_ID":"2","myTab_xam":"test2","myTab_rank":"22"},{"myTab_ID":"3","myTab_xam":"test3","myTab_rank":"22"}]}"
in the error console.
I am a little happy that I atleast am able to get the data from my php side to the html file, but now I am wonder how would I use that returned JSON data. How would I develop the callback function that returns the JSON data back??
> ------code in getData.php---------------
>
> $con =
> mysql_connect("localhost","peter","abc123");
> if (!$con) { die('Could not
> connect: ' . mysql_error()); }
>
> mysql_select_db("my_db", $con);
>
> $result = mysql_query("SELECT * FROM
> Persons");
>
> while($row =
> mysql_fetch_array($result)) {
> $data[] = $row; }
>
> echo json_encode($data);
>
> --------------end - getdata.php--------------
>
> ---------code in getJson.html------------- html> <head>
> <script type="text/javascript"
> src="http://myserver/getdata.php">
> </script> </head>
>
> </html>
> -----------------------end- getJson.html----------
I am not sure how a callback would work to get the data?
-
When putting code in your questions, just indent each line by 4 spaces.Pointy– Pointy2011年01月14日 16:21:31 +00:00Commented Jan 14, 2011 at 16:21
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@Pointy - you can also just highlight it and click the {} buttonParris Varney– Parris Varney2011年01月14日 16:32:56 +00:00Commented Jan 14, 2011 at 16:32
3 Answers 3
Don't forget your header in getData.php:
header('Content-type: application/json');
-
When I add this header, the file is coming up for download. As soon as I load a page, I am getting a prompt for downloading the getData.php file. Is this wierd?macha– macha2011年01月14日 16:27:28 +00:00Commented Jan 14, 2011 at 16:27
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Is that when you are trying to view the output through a browser? There are various methods of getting browsers to interpret application/json - eg. adallow.wordpress.com/2008/10/13/…Ken– Ken2011年01月16日 17:23:44 +00:00Commented Jan 16, 2011 at 17:23
You're getting that error because that JSON construction is simply erroneous to the JavaScript parser. After a naked open curly brace ({), Javascript expects a statement.
What your code seems to expect is that the JSON not be included simply as a <script> into a page, but instead that it be fetched actively by an XMLHttpRequest (i.e., "ajax"). That's really common, and it's quite different from what a <script> tag gives you. In such situations, the JSON construction is explicitly parsed by client-side code and used for, well, whatever is desired.
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Correct; as-is, your HTML page is trying to include JSON as JavaScript, which fails. You need to assign it to a variable, either through an AJAX call, or the PHP page needs to output it as a variable (
var myData = {...}).MidnightLightning– MidnightLightning2011年01月14日 16:38:25 +00:00Commented Jan 14, 2011 at 16:38 -
how can I assign the output as a variable? do I just return the json_encode($data)?? or would I have write some javascript inside my php and return that??macha– macha2011年01月14日 16:44:03 +00:00Commented Jan 14, 2011 at 16:44
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If the PHP code wrote the JSON out with a little Javascript around it, that would work fine, as others have noted. Just have the PHP code prefix that JSON with the JavaScript code to declare a variable, like
var x = { json stuff here };Pointy– Pointy2011年01月14日 17:01:13 +00:00Commented Jan 14, 2011 at 17:01 -
Assume $data contains the json data, so do I do a echo '<script> var myData = "<?php $data; ?>"</script>'; Is this what you would suggest Pointy?macha– macha2011年01月14日 17:08:52 +00:00Commented Jan 14, 2011 at 17:08
if you want the json encoded $data array to be avaliable in javascript you can do this:
<?php $jencodeddata = json_encode($data); ?>
in your HTML file..
<script type="text/javascript">
function doSOmething()
{
var jsencodedata = '<?php print $jencodeddata ?>';
you can loop through jsencodedata here....
}
</script>
hope this helps.
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