Как передать другому html документу параметр

function readCookie(name) {
var cookieValue = "";
var search = name + "=";
if (document.cookie.length > 0) {
offset = document.cookie.indexOf(search);
if (offset != -1) {
offset += search.length;
end = document.cookie.indexOf(";", offset);
if (end == -1) end = document.cookie.length;
cookieValue = unescape(document.cookie.substring(offset, end))
}
}
return cookieValue;
}

function writeCookie(name, value, hours) {
var expire = "";
if(hours != null) {
expire = new Date((new Date()).getTime() + hours * 3600000);
expire = "; expires=" + expire.toGMTString();
}
document.cookie = name + "=" + escape(value) + expire;
}
function alMsg() {
var msg = "Твоё сообщение";
if (readCookie('alerted')=="") {
alert(msg);
writeCookie('alerted','1',24);
}
}