function FixForm(){
var form = document.forms[0];
for (i=0;i<form.elements.length; i++){
    var nazwa   = form.elements[i].name;
    var wartosc = form.elements[i].value;
    }
}

function FixForm(){
    var form = document.forms[0];
    var childs = form.childNodes;
    for (i=0;i<form.elements.length; i++){
        var nazwa   = form.elements[i].name;
        var wartosc = form.elements[i].value;
        if(form.elements[i].type=="checkbox") {
            //...
        }
    }
}