function isValidEmail(field) 
    {
        var reg1 = /(@.*@)|(\.\.)|(@\.)|(\.@)|(^\.)/; 
        var reg2 = /^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?)$/; 
        if (!reg1.test(field) && reg2.test(field)) { return true; } else{ return false; }
    }

    function validate() 
    {
        name    = getValue("name");
        email   = getValue("email");
        comment = getValue("comment");

        if (name == "") { hideAllErrors(); inline("nameError"); focus("name"); return false; }  
        else if (email == "" || !isValidEmail(email)) { hideAllErrors(); inline("emailError"); focus("email"); return false; } 
        else if (comment == "") { hideAllErrors(); inline("commentError"); focus("comment"); return false; }
        return true;
    }
    
    function getValue(field) { var value; value = document.getElementById(field).value; return value; }
    function inline(field) { var value; value = document.getElementById(field).style.display = "inline"; return value; }
    function focus(field) { var value; value = document.getElementById(field).focus(); return value; }
 
    function hideAllErrors(field) 
    {
        document.getElementById("nameError").style.display = "none"
        document.getElementById("emailError").style.display = "none"
        document.getElementById("commentError").style.display = "none"
    }