function check_empty(ctrl,id,form, ctrlname)
{
	obj = eval("document." + form + "." + ctrl)
	if (!obj)
	{
		alert (ctrl + " is not an object!")
		return 0
	}
	if (obj.value.length == 0)
	{
		alert ("Please fill in " + id)
		obj.focus();
		return 1
	}
	return 0
}

function check_email(ctrl, form) 
{
	obj = eval("document." + form + "." + ctrl)
	if (!obj)
	{
		alert (ctrl + " is not an object!")
		return 0
	}
	   
	// Return false if e-mail field does not contain an '@' and a '.'.
    if (obj.value.indexOf ('@',0) == -1 || obj.value.indexOf ('.',0) == -1)
    {
        alert("Invalid email address!");
		obj.focus();
        return 1
    }
    return 0
}

function isInteger(s){
	var i;
    for (i = 0; i < s.length; i++){   
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}