function opwin(winurl,wx,wy)
 
  {
  	var winl = (screen.width - wx) / 2;
	var wint = (screen.height - wy) / 2;

 
    wx = wx + 20;
 
    wy = wy + 20;
 
 if (wy > 550) {wy = 550};
 
    winname = "w" + Math.round(Math.random() * 1000); 
 
    wstr = "scrollbars=no,menubar=no,width="+wx+",height="+wy+"top="+wint+",left="+winl;
 
    window.open("mostra.htm",winurl,wstr);
 
  }
 
function isValidDate(beginDate,endDate) {
	
	var now = new Date();
	
	var dt;
	var dtend;
	
	dt = getDate(beginDate);	
	dtend = getDate(endDate);
	
	if (dt.getTime()>=dtend.getTime()) 
	{
				return false;
	}
	else
		return true;
}


function getDate(dateString)
{
	var tokens = dateString.split("-");
	var dt = new Date(tokens[2],tokens[1]-1,tokens[0]);
	return dt;
}


function emailCheck(emailStr) 
{
	/*
		The following pattern is used to check if the entered e-mail address
		fits the user@domain format.  It also is used to separate the username
		from the domain. 
	*/
	var emailPat=/^(.+)@(.+)$/

	/*
		The following string represents the pattern for matching all special
		characters.  We don't want to allow special characters in the address. 
		These characters include ( ) < > @ , ; : \ " . [ ]    
	*/
	var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]"

	/*
		The following string represents the range of characters allowed in a 
		username or domainname.  It really states which chars aren't allowed. 
	*/
	var validChars="\[^\\s" + specialChars + "\]"

	/*
		The following pattern applies if the "user" is a quoted string (in
		which case, there are no rules about which characters are allowed
		and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
		is a legal e-mail address. 
	*/
	var quotedUser="(\"[^\"]*\")"

	/*
		The following pattern applies for domains that are IP addresses,
		rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
		e-mail address. NOTE: The square brackets are required. 
	*/
	var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/

	/*
		The following string represents an atom (basically a series of
		non-special characters.) 
	*/
	var atom=validChars + '+'

	/*
		The following string represents one word in the typical username.
		For example, in john.doe@somewhere.com, john and doe are words.
		Basically, a word is either an atom or quoted string.
	*/
	var word="(" + atom + "|" + quotedUser + ")"

	// The following pattern describes the structure of the user
	var userPat=new RegExp("^" + word + "(\\." + word + ")*$")

	/*
		The following pattern describes the structure of a normal symbolic
		domain, as opposed to ipDomainPat, shown above. 
	*/
	var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$")
 

	/*
		Finally, let's start trying to figure out if the supplied address is
		valid.
	*/
 
	/*
		Begin with the coarse pattern to simply break up user@domain into
		different pieces that are easy to analyze.
	*/
	var matchArray=emailStr.match(emailPat)
	if (matchArray==null)
	{
		/*
			Too many/few @'s or something; basically, this address doesn't
			even fit the general mould of a valid e-mail address.
		*/
		//alert("Email address seems incorrect (check @ and .'s)")
		return false
	}
	var user=matchArray[1]
	var domain=matchArray[2]
 
	// See if "user" is valid 
	if (user.match(userPat)==null) 
	{
		// user is not valid
		//alert("The username doesn't seem to be valid.")
		return false
	}
 
	/*
		if the e-mail address is at an IP address (as opposed to a symbolic
		host name) make sure the IP address is valid.
	*/
	var IPArray=domain.match(ipDomainPat)
	if (IPArray!=null) 
	{
		// this is an IP address
		for (var i=1;i<=4;i++)
		{
			if (IPArray[i]>255) 
			{
				//alert("Destination IP address is invalid!")
				return false
			}
		}
	return true
	}
 
	// Domain is symbolic name
	var domainArray=domain.match(domainPat)
	if (domainArray==null) 
	{
		//alert("The domain name doesn't seem to be valid.")
		return false
	}
 
	/*
		domain name seems valid, but now make sure that it ends in a
		three-letter word (like com, edu, gov) or a two-letter word,
		representing country (uk, nl), and that there's a hostname preceding 
		the domain or country. 
	*/
 
	/* Now we need to break up the domain to get a count of how many atoms
		it consists of.
	*/
	var atomPat=new RegExp(atom,"g")
	var domArr=domain.match(atomPat)
	var len=domArr.length
	if (domArr[domArr.length-1].length<2 || 
		domArr[domArr.length-1].length>3) 
	{
		// the address must end in a two letter or three letter word.
		//alert("The address must end in a three-letter domain, or two letter country.")
		return false
	}
 
	// Make sure there's a host name preceding the domain.
	if (len<2) 
	{
		var errStr="This address is missing a hostname!"
		//alert(errStr)
		return false
	}
 
	// If we've gotten this far, everything's valid!
	return true;
}