function getPageUrl()
{
	if (getQueryVariable("url"))
		return getQueryVariable("url");
	else if (window.opener)
		return window.opener.document.location.href;
	else
		return ("Error: This page must be opened in a popup window or must be passed a 'url' querystring value.");
}

function getQueryVariable(variable)
{
	var query = window.location.search.substring(1);
	var vars = query.split("&");
	for (var i = 0; i < vars.length; i++)
	{
		var pair = vars[i].split("=");
		if (pair[0] == variable)
			return pair[1];
	}
	return false;
}

function validate(theForm)
{
	var strError = "";
	if (theForm.sender_name.value == "")
		strError += "Your name\n";
	if (!isValidEmail(theForm.sender_email.value))
		strError += "Your email\n";
	if (!isValidEmail(theForm.recipient.value))
		strError += "Friend's email\n";
	if (strError != "") {
		alert("The following fields had errors:\n\n" + strError + "\nPlease try again.");
		return false;
	}
	else {
		return true;
	}
}

function isValidEmail(strInput)
{
  var regex = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;
  return regex.test(strInput);
}