function validate_required(field,alerttxt)
{
with (field)
{
if (value==null||value=="")
  {alert(alerttxt);return false;}
else {return true}
}
}
function validate_email(field,alerttxt)
{
with (field)
{
apos=value.indexOf("@");
dotpos=value.lastIndexOf(".");
if (apos<1||dotpos-apos<2) 
  {alert(alerttxt);return false;}
else {return true;}
}
}

function validate_form(thisform)
{
with (thisform)
{
if (validate_required(name,"Please enter your name.")==false)
  {name.focus();return false;}
if (validate_email(email,"Please enter a valid email.")==false)
  {email.focus();return false;}
if (validate_required(friend_name,"Please enter your friends name.")==false)
  {friend_name.focus();return false;}
if (validate_email(friend_email,"Please enter your friends email.")==false)
  {friend_email.focus();return false;}
}
}
function bookmark(url,title){
  if ((navigator.appName == "Microsoft Internet Explorer") && (parseInt(navigator.appVersion) >= 4)) {
  window.external.AddFavorite(url,title);
  } else if (navigator.appName == "Netscape") {
    window.sidebar.addPanel(title,url,"");
  } else {
    alert("Press CTRL-D (Netscape) or CTRL-T (Opera) to bookmark");
  }
}