function check_search()
{
	if (document.search_form.search.value.length == 0){
		alert("Please first fill search parameter."); 
		document.search_form.search.focus();
		return false;
	}
	else {
		return true;
	}
}

function check_login()
{
	if (document.user_login.username.value.length == 0){
	alert("Please first fill your user name."); 
	document.user_login.username.focus();
	return false;
	}
	if (document.user_login.password.value.length == 0){
	alert("Please first fill your password."); 
	document.user_login.password.focus();
	return false;
	}
	else {
	return true;
	}
}