I'm POSTing the contents of a form field via AJAX to a PHP script and using JavaScript to escape(field_contents). The problem is that any plus signs are being stripped out and replaced by spaces. How can I safely 'encode' the plus sign and then appropriately 'decode' it on the PHP side?
Use encodeURIComponent() in JS and in PHP you should receive the correct values.
Note: When you access $_GET, $_POST or $_REQUEST in PHP, you are retrieving values that have already been decoded.
Example:
In your JS:
// url encode your string
var string = encodeURIComponent('+'); // %2B
// send it to your server
window.location = 'http://example.com/?string='+string; // http://example.com/?string=%2B
On your server:
echo $_GET['string']; // +
It is only the raw HTTP request that contains the url encoded data.
For a GET request you can retrieve this from the URI. $_SERVER['REQUEST_URI'] or $_SERVER['QUERY_STRING']. For a urlencoded POST, file_get_contents('php://stdin')
NB:
decode() only works for single byte encoded characters. It will not work for the full UTF-8 range.
eg:
text = u0100; // Ā
// incorrect
escape(text); // %u0100
// correct
encodeURIComponent(text); // %C4%80
Note: %C4%80 is equivalent to: escape('xc4x80')
Which is the byte sequence (xc4x80) that represents Ā in UTF-8. So if you use encodeURIComponent() your server side must know that it is receiving UTF-8. Otherwise PHP will mangle the encoding.
