function valid()
{
a=document.form.paper_type.selectedIndex;
b=document.form.organizer.selectedIndex;
c=document.form.paper_subject.selectedIndex;
if (document.form.paper_type.options[a].value=="empty")
	{
	alert("Please select a type of paper from the popup list.");
	return false;
	}
if (document.form.organizer.options[b].value=="empty")
	{
	alert("Please select a session organizer from the popup list.");
	return false;
	}	
if (document.form.paper_subject.options[c].value=="empty")
	{
	alert("Please select a classification from the popup list.");
	return false;
	}
if(document.form.first_name.value=="")
	{
		document.form.first_name.focus();
		alert("Please enter your first name.")
		return false;
	}
if(document.form.last_name.value=="")
	{
		document.form.last_name.focus();
		alert("Please enter your last name.");
		return false;			
	}
	

if(document.form.affiliation.value=="")
	{
		document.form.affiliation.focus();
		alert("Please enter your affiliation.");
		return false;			
	}
if(document.form.email.value=="")
	{
		document.form.email.focus();
		alert("Please enter your email address.");
		return false;			
	}
if(document.form.title.value=="")
	{
		document.form.title.focus();
		alert("Please enter the title of your abstract.");
		return false;			
	}

}