jQuery $.ajax POST Request with IE 9 results empty array

jQuery $.ajax POST Request with IE 9 results empty array

I have a problem with my Coding, so in Firefox it works fine but in IE9 it
only works for the first ~5 seconds. After that time i don't receive any
POST Data anymore.
I want to load a PHP page via AJAX using the values of form inputs as POST
variables. The first 5 seconds i can receive the POST on the requested
page but after that i only receive an empty string.
Here is my Code:
function reload_form(){
var data = $("#formularfelder").serialize()
$.ajax({
type: 'POST',
url: 'content/formular.php',
data: data,
success: function(msg) {
$("#form_container").html(msg);
}
});
}
Is it a bug of IE9 and is there a workaround available?
It would be awesome if you could help me! :)