function verifyForm() {
	
	if (isEmpty(myform.yourname.value)) { notifyMissing('yourname','your name');return; }
	if (isEmpty(myform.youremail.value)) { notifyMissing('youremail','your email address');return; }
	if (isEmpty(myform.friendsemail.value)) { notifyMissing('friendsemail','your friends email address');return; }

	if (!(isEmail(myform.youremail.value))) { notifyInvalid('youremail','your email address');return; }
	if (!(isEmail(myform.friendsemail.value))) { notifyInvalid('friendsemail','your friends email address');return; }

	
	myform.submit()

}

function isEmpty(s)
{   return ((s == null) || (s.length == 0))
}

function notifyMissing (theField, s)
{   eval("myform."+theField+".focus()")
    alert('Please enter ' + s)
    return false
}

function notifyInvalid (theField, s)
{   eval("myform."+theField+".focus()")
    eval("myform."+theField+".select()")
    alert('You have entered an invalid response for ' + s)
    return false
}

function isNumeric(s,minLen)

{   var i;

    s = s.replace(/ /g,'')

    if (s.length<minLen) return false;

    for (i = 0; i < s.length; i++)
    {   
        var c = s.charAt(i);

        if (! (isDigit(c)) )
        return false;
    }

    return true;
}

function isDigit (c)
{   return ((c >= "0") && (c <= "9"))
}


function isEmail (s)
{   
    var i = 1;
    var sLength = s.length;

    while ((i < sLength) && (s.charAt(i) != "@"))
    { i++
    }

    if ((i >= sLength) || (s.charAt(i) != "@")) return false;
    else i += 2;

    while ((i < sLength) && (s.charAt(i) != "."))
    { i++
    }

    if ((i >= sLength - 1) || (s.charAt(i) != ".")) return false;
    else return true;
}