Html - Javascript and Cookies - Need help

Hello, I need alittle help finishing my code.

<script LANGUAGE="JavaScript">

cookie_name = "dataCookie";

var YouEntered;

function putCookie() {

if(document.cookie != document.cookie)

{index = document.cookie.indexOf(cookie_name);}

else

{ index = -1;}

if (index == -1)

{

YouEntered=document.cf.cfd.value;

document.cookie=cookie_name+"="+YouEntered+"; expires=Monday, 04-Apr-2010 05:00:00 GMT";

}

}

</SCRIPT>

<FORM NAME="cf">

Enter A Word: <INPUT TYPE="text" NAME="cfd" size="20">

<INPUT TYPE="button" Value="Set to Cookie"

onClick="putCookie()">

</FORM>

I can't figure out how to make a reset button to delete the cookie so a new text can be stored in the box.

Also is there any specific I need to type in if I want the box only to save Links?