function login_cf(){
	var msg = '';
	var f;
	
	f = document.loginform;

	if( f.email.value=="" )			msg=msg+'Please enter your email address.\n';
	else if( !emailOK(f.email.value) )	msg=msg+'Please check out your email address.\n';
	if( f.password.value=="" )		msg=msg+'Please enter your password.\n';

	if( msg!="" ){
		window.alert(msg);
		return false;
	} else {
		return true;
	}
}

function lostpass_cf(){
	var msg = '';
	var f;
	
	f = document.lostpassform;

	if( f.personEmail.value=="" )			msg=msg+'Please enter your email address.\n';
	else if( !emailOK(f.personEmail.value) )	msg=msg+'Please check out your email address.\n';

	if( msg!="" ){
		window.alert(msg);
		return false;
	} else {
		return true;
	}
}

function register_cf(){
	var msg = '';
	var f;
	
	f = document.registerform;

	if( f.personFirstname.value=="" )		msg=msg+'Please enter your first name.\n';
	if( f.personLastname.value=="" )		msg=msg+'Please enter your last name.\n';
	if( f.personInstitution.value=="" )		msg=msg+'Please enter your institution.\n';
	if( f.personDepartment.value=="" )		msg=msg+'Please enter your department.\n';
	if( f.personAddress.value=="" )			msg=msg+'Please enter your address.\n';
	if( f.personZIP.value=="" )			msg=msg+'Please enter your ZIP code.\n';
	if( f.personCity.value=="" )			msg=msg+'Please enter your city.\n';
	if( f.personCountry.value=="" )			msg=msg+'Please enter your country.\n';
	if( f.personEmail.value=="" )			msg=msg+'Please enter your email address.\n';
	else if( !emailOK(f.personEmail.value) )	msg=msg+'Please check out your email address.\n';

	if( msg!="" ){
		window.alert(msg);
		return false;
	} else {
		return true;
	}
}

function paper_cf() {
	var msg = '';
	var f;
	var doc1,doc2;
	
	f = document.paperform;

	doc1 = f.file1.value.toLowerCase();
	doc2 = f.file2.value.toLowerCase();

	if( f.paperTitle.value=="" )		msg=msg+'Please enter the title.\n';
	if( f.file1.value!="" )	
		if( doc1.indexOf(".pdf") == -1 )	msg=msg+'pdf only are allowed as Anonymous version.\n';
	if( f.file2.value!="" )	
		if( doc2.indexOf(".pdf") == -1 )	msg=msg+'pdf only are allowed as Affiliated version.\n';

	if( msg!="" ){
		window.alert(msg);
		return false;
	} else {
		return true;
	}
}

function emailOK(value){
	with (value){
		apos=value.indexOf("@"); 
		dotpos=value.lastIndexOf(".");
		lastpos=value.length-1;
		if( apos<1 || dotpos-apos<2 || lastpos-dotpos>4 || lastpos-dotpos<2 ){
			return false;
		} else {
			return true;
		}
	}
}

function ask_first(question) {
	return confirm(question);
}