function createxhr() 
{
    var xhr = false;
        try {
            xhr = new ActiveXObject('Msxml2.XMLHTTP');
        }
        catch (err2) {
            try {
                xhr = new ActiveXObject('Microsoft.XMLHTTP');
            }
            catch (err3) {
		try {
			xhr = new XMLHttpRequest();
		}
		catch (err1) 
		{
			xhr = false;
		}
            }
        }
    return xhr;
}