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_email(email,"Not a valid e-mail address!")==false){
            email.focus();
            return false;
        }
        else{return true;}
    }
}