function ValidateForm(form)
{
    return Checkfields(form);
}
function Checkfields(form)
{
    var bool = true;
    var msg = "<div style=\"color: red;\">De volgende velden zijn niet (correct) ingevuld:";
    for(var i=0; i<form.length; i++)
    {
        field = form[i];
        if(field.validate == "true" && field.value=="")
        {
            field.style.border = "solid 2px red";
            msg += "<li>" + field.name + "</li>";
            bool = false;
        }
    }
    msg += "<br /></div>";
    
    if(!bool)
    {
        formHTML = form.innerHTML;
        form.innerHTML = msg + formHTML;
    }
    
    return bool;
}