What's the alert box cannot be displayed?

[phpuser123]

I have a function that takes a base url and appends values dynamically from a form.However, the success alert box is not displayed.. What's wrong with these codes and How to sort this?

 function validateEncode(url,frm,id){
               alert(url.toString().length)
               Form = document.forms[frm].elements;
                    var URL="";
                    var encodedurl;
                    alert(url);
                   for (i=0;i<=Form.length;i++)
                        {
                            URL+="test"+Form[i].name;
                        }

                   //urlObject.setAttribute('href', url+encodedurl)
                  alert("success");
               
             return false;
            }

[Dormilich]

line #7: the last cycle causes an error. change to for (i=0;i<Form.len gth;i++)