How to record visitor's name by Cookie

function getCookieVal (offset) {
  var endstr = document.cookie.indexOf (";",offset);
  if (endstr == -1)
  endstr = document.cookie.length;
  return unescape(document.cookie.substring(offset,endstr));
}

function GetCookie (name) {
  var arg = name   "=";
  var alen = arg.length;
  var clen = document.cookie.length;
  var i = 0;
  while (i < clen) {
    var j = i   alen;
    if (document.cookie.substring(i,j) == arg)
    return getCookieVal (j);
    i = document.cookie.indexOf(" ",i)   1;
    if (i == 0) break;
  }
  return null;
}

function SetCookie (name,value) {
  var argv = SetCookie.arguments;
  var argc = SetCookie.arguments.length;
  var expires = (argc > 2) ? argv[2] : null;
  var path = (argc > 3) ? argv[3] : null;
  var domain = (argc > 4) ? argv[4] : null;
  var secure = (argc > 5) ? argv[5] : false;
  document.cookie = name   "="   escape (value) 
   ((expires == null) ? "" : ("; expires="   expires.toGMTString())) 
   ((path == null) ? "" : ("; path="   path)) 
   ((domain == null) ? "" : ("; domain="   domain)) 
   ((secure == true) ? "; secure" : "");
}

//      - - - - - - - - End of Public Domain Cookie Code - - - - - - - -
//      - - - - - - - - JTotW Cookie Functions by Nick Heinle- - - - - - - -

function show_count() {
  var expdate = new Date();
  var num;
  expdate.setTime(expdate.getTime()    (24 * 60 * 60 * 1000 * 31));
  if(!(num = GetCookie("jtotwcount")))
  num = 0;
  num  ;
  SetCookie ("jtotwcount",num,expdate);
  if (num == 1) document.write("Since this is the first time you have been here,please take a moment to look around.");
  else document.write("You have been here "   num   " times.");
}

function auto_show_name() {
  if(GetCookie("jtotwname") != null)
  document.write("Welcome back to this week's tip "   GetCookie('jtotwname')   ". ");
  else {
  document.write("<FORM>Please enter your name: <INPUT TYPE = "text" NAME = "nameinput">"   "<BR><BR><INPUT TYPE = "button" VALUE = "Save to Cookie" onClick = "set_name(this.form)"></FORM>");
  document.write("Please enter your first name in the input"   " box and press the "Save to Cookie" button,then the page will automatically reload. ");
  }
}

function set_name(form) {
  var expdate = new Date ();
  expdate.setTime (expdate.getTime()   (24 * 60 * 60 * 1000 * 31));
  var username = form.nameinput.value
  if (username != "") {
    if (confirm("Are you sure you want this saved as your name?")) {
      SetCookie ("jtotwname",username,expdate);
      window.history.go(0);
    }
  } else alert("Geez,at least enter something,entering nothing will cause an error.");
}

<html>
<head>
  <title>KURAPA.COM</title>
  <script type="text/javascript" src="userName.js"></script>
</head>
<body>
<form>
Please enter your name: <input type="text" name="nameinput">
<br><br>
<input type="button" value="Save to Cookie" onclick="set_name(this.form)">
</form>
</body>
</html>