Ajax post- Cross domain request XDR

This is my JavaScript code to make XDR post request:

if(isIE()) {
    xdr = new XDomainRequest();
    if (xdr) {
        xdr.onerror = err;
        xdr.ontimeout = timeo;
        xdr.onload = loadd;
        xdr.timeout = 10000;
        xdr.open('POST', url);
        xdr.send('myval=abc'); 
    } 
}

Select allOpen in new window

And when I try to access the variable myval in PHP:

if(isset($HTTP_RAW_POST_DATA)) {
  parse_str($HTTP_RAW_POST_DATA); // here you will get variable $myval
  if($myval== 'abc') {
  echo "TRUE !";
  }
}
else {
 echo 'NO POST DATA';
}

Select allOpen in new window

I get the output as 'NO POST DATA'. Could anyone help me in finding what is wrong here? Many thanks.