function openWindow(URL){

	var w, h;

	w = 640;
	h = 510;

	var isMac = (navigator.appVersion.indexOf("Mac") != -1);
	var isNetscape = (!(navigator.appName.indexOf("Microsoft") != -1));
	var isVersion7 = (navigator.userAgent.indexOf("Netscape/7") != -1);

	if (isMac)
		BookURL += "&IsMac=1";
	if (isNetscape)
		BookURL += "&IsNetscape=1";
	if (isVersion7)
		BookURL += "&BrowserVersion=7";
	if ((!isMac) && (isNetscape) && (isVersion7))
		h -= 50;
	if ((isMac) && (isNetscape))
		h -= 55;

	var iwindowHand = window.open(URL, "document", "fullscreen=no,resizable=yes,status=yes,toolbar=no,menubar=no,location=no,width="+w+",height="+h+",top=0,left=0");
	
	if (iwindowHand == null || typeof(iwindowHand)=="undefined")	
	    alert ("Please disable your popup blocker");
	else {
	    iwindowHand.focus();
	}
    
}

<!--

function MM_swapImgRestore() { //v3.0

  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;

}

 

function MM_preloadImages() { //v3.0

  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();

    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)

    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}

}

 

function MM_findObj(n, d) { //v4.01

  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {

    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}

  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];

  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);

  if(!x && d.getElementById) x=d.getElementById(n); return x;

}

 

function MM_swapImage() { //v3.0

  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)

   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}

}

//-->



function HideContent(d) {
document.getElementById(d).style.display = "none";
}
function ShowContent(d) {
document.getElementById(d).style.display = "block";
}
function ReverseDisplay(d) {
if(document.getElementById(d).style.display == "none") { document.getElementById(d).style.display = "block"; }
else { document.getElementById(d).style.display = "none"; }
}

function checkform()
{
	if (frmLogin.txtusername.value == '') {
	alert('You must enter a Username');
	frmLogin.txtusername.focus();
	return false;
	}

	else if (frmLogin.txtpassword.value == '')
	{
		alert('You must enter a password');
		frmLogin.txtpassword.focus();
		return false;
	}

	return true;
}