Google Chrome showing javascript security error

Question

I need help resolving this Google Chrome Error..."Uncaught Error: SECURITY_ERR: DOM Exception 18"

Here is the code.

//Get Cookie
function get_cookie (cookie_name)
{
    var results = document.cookie.match ( '(^|;) ?' + cookie_name + '=([^;]*)(;|$)' );
    if (results)
    return ( unescape ( results[2] ) );
    else
    return null;
};

Many thanks, C