function Is ()
{   
    var agt=navigator.userAgent.toLowerCase();
    var ieMajor;
    this.major = parseInt(navigator.appVersion);
    this.minor = parseFloat(navigator.appVersion);
    ieMajor = msieversion();
    this.nav  = ((agt.indexOf('mozilla')!=-1) && ((agt.indexOf('spoofer')==-1) && (agt.indexOf('compatible') == -1)));
    this.ie   = (agt.indexOf("msie") != -1);
    this.nav6up = this.nav && (this.major >= 5);
    this.ie4up  = this.ie  && (ieMajor >= 4);
    return this;
}

function msieversion()
{
      var ua = window.navigator.userAgent;
      var msie = ua.indexOf ( "MSIE " );
      if ( msie > 0 )      // If Internet Explorer, return version number
         return parseInt (ua.substring (msie+5, ua.indexOf (".", msie )));
      else                 // If another browser, return 0
         return 0;

}

function callback()
{
BrowserVer = Is();
if (!window.windowCallBack)
{
	if (BrowserVer.ie4up || BrowserVer.nav6up)
		{
		open_CallBack();
		}
	else
		{
		alert("Only Netscape Navigator 6.0 and Internet Explorer 4.0\nand above browsers are supported by the Call Back feature.");
		}
}
else
{
	if (!windowCallBack.closed)
	{
	windowCallBack.focus();
	}
	else
	{
	open_CallBack();
	}
}
}

function open_CallBack()
{
	// center new window in current window
	var intWidth = 350;
	var intHeight = 350;
	var intLeft = 50;
	var intTop = 0;
	var strParameters = "toolbar=no,location=no,directories=no,menubar=no,scrollbars=no,top=yes,width=" + intWidth + ",height=" + intHeight;
	if (navigator.appName.indexOf("Microsoft")>=0)
		{
		intLeft = (screen.width - intWidth) / 2;
		intTop = (screen.height - intHeight) / 2;
        strParameters+=",left=" + intLeft + ",top=" + intTop;
        }
	else
		{
		intLeft = window.screenX + ((window.outerWidth - intWidth) / 2);
		intTop = window.screenY + ((window.outerHeight - intHeight) / 2);
        strParameters+=",screenX=" + intLeft + ",screenY=" + intTop;
        }
	windowCallBack = window.open("callback.aspx", "RefCallBack", strParameters);
}