<a href="">Поменять ник</a>

<SCRIPT LANGUAGE="JavaScript"> 
var username = GetCookie('username');
if (username == null) {
username = prompt('Введите ваш ник на АНГЛИЙСКОМ!',"");
 if (username == null) {
alert('Вы не ввели ваш ник, так что будет наш =) ');
username = 'unnamed';
 
  } else {
 
    // don't set the username cookie.... because the user refused to tell you.
    // they will be prompted next time....
 
    pathname = location.pathname;
    myDomain = pathname.substring(0,pathname.lastIndexOf('/')) +'/';
 
    // set expiry date to 1 year from now.
    var largeExpDate = new Date ();
    largeExpDate.setTime(largeExpDate.getTime() + (30 * 24 * 3600 * 1000));
 
    SetCookie('username',username,largeExpDate,myDomain);
  }
 
}
 
 
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" : "");
}
var today = new Date ()
var hrs = today.getHours();

document.writeln("тест");
document.writeln("ник: "+ username +"");



</SCRIPT>

<script type="text/javascript">
function setcookie(a,b,c) {if(c){var d = new Date();d.setTime(d.getTime()+c);}if(a && b) document.cookie = a+'='+b+';path=/'+(c ? '; expires='+d.toUTCString() : '');else return false;}
 function getcookie(a) {var b = new RegExp(a+'=([^;]){1,}');var c = b.exec(document.cookie);if(c) c = c[0].split('=');else return false;return c[1] ? c[1] : false;}
function deletecookie( name) {if ( getcookie( name ) ) document.cookie = name + '=1; expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/';}
</script>
</script>
<script type="text/javascript">
setcookie("Test",22222);
alert(getcookie("Test"))
deletecookie("Test")
alert(getcookie("Test"))

</script>

<a href="" onclick="del_cookie(name)">Поменять ник</a>
и
<a href="" onclick="del_cookie()">Поменять ник</a>

<a href="" onclick="del_cookie('name')">Поменять ник</a>
и
<a href="" onclick="del_cookie('')">Поменять ник</a>

function del_cookie (name) {
document.cookie = 'name' + '=; expires=Thu, 01-Jan-70 00:00:01 GMT;';
}

<SCRIPT LANGUAGE="JavaScript">
 function setCookie(name, value, expires, path, domain, secure) {
 document.cookie = name + "=" + escape(value) +
 ((expires) ? "; expires=" + expires.toGMTString() : "") +
 ((path) ? "; path=" + path : "") +
 ((domain) ? "; domain=" + domain : "") +
 ((secure) ? "; secure" : "")
 }
 function getCookie(name) {
 var prefix = name + "="
 var cookieStartIndex = document.cookie.indexOf(prefix)
 if (cookieStartIndex == -1) return null
 var cookieEndIndex = document.cookie.indexOf(";", cookieStartIndex + prefix.length)
 if (cookieEndIndex == -1) cookieEndIndex = document.cookie.length
 return unescape(document.cookie.substring(cookieStartIndex + prefix.length, cookieEndIndex))
 }
 function fixDate(date) {
 var base = new Date(0)
 var skew = base.getTime()
 if (skew > 0) date.setTime(date.getTime() - skew)
 }
 var now = new Date()
 fixDate(now)
 now.setTime(now.getTime() + 365 * 24 * 60 * 60 * 1000)
 var nam = getCookie("login")
 setCookie("login", nam, now)
 function ok() {
 setCookie("login", document.f.login.value, now)
 window.location.reload();
 }
 document.write('<form name="f">Ваше имя: <input type="text" name="login" size="10"><input type="button" value="ОК" onClick="ok();"></form>')
 </SCRIPT>
 <!--Второй скрипт для вывода имени-->
 <SCRIPT LANGUAGE="JavaScript">
 var nam = getCookie("login")
 if (!nam) {document.write("<b>Привет!!!</b><br/>")} else {document.write("<b>Привет " + nam + "</b><br/>")}
 </SCRIPT>