function emptyvalidation(entered, alertbox)
{
with (entered)
{
if (value==null || value=="")
{if (alertbox!="") {alert(alertbox);} return false;}
else {return true;}
}
} 


function emailvalidation(entered, alertbox)
{
with (entered)
{
apos=value.indexOf("@"); 
dotpos=value.lastIndexOf(".");
lastpos=value.lengtha;
if (apos<1 
|| dotpos-apos<2 || lastpos-dotpos>3 || lastpos-dotpos<2) 
{if (alertbox) {alert(alertbox);} return false;}
else {return true;}
}
} 
function formvalidation(thisform)
{

with (document.f)
{
if (emptyvalidation(firstname,"The First Name field cannot be left blank.  Please enter your first name.")==false) {firstname.focus(); return false;};
if (emailvalidation(emailaddr,"The Email Address field cannot be left blank and must be in the correct format.  Please enter your email address in the format myname@mycompany.com.")==false) {emailaddr.focus(); return false;};
}
}