414 Request-URI Too Large - MooTools

When URI is longer than 256 characters, request string produce error.

The difference between GET and POST is that with a GET, you encode all parameters in the URL; with a POST, you send them in the request body, not the URL. So the URL length limit applies (this is largely the original reason for POST). 

FIX: Replace method get to post

new Request.HTML({
var req = url:getData.php,
method: post,
data: {do:'1'}
}).send();