Remove DIV (ajax)

how to remove the old div

[Zosia]

hi you guys =)
i want to remove div element dynamically

// ajax stuff...................
// checking *onlineusers* page for online users

results = httpO.responseText.split('---');
for(i=0;i < (results.length....la la la

// now results[i+3] is USERID

var FindMe=document.getElementById(results[i+3]);

// here we create a new div if new user login in = )

if(!FindMe) {
document.getElementById("OnLineUsers").innerHTML+="<div id='"+results[i+3]+"'>USERNAME</div>";
}

// so i don't know how to remove the user's div when it's time < exptime
// i mean when user has closed the window, i need to remove user's name (div) from the page

there is no *old_username* on *onlineusers* page anymore , when user has closed the browser..
but it still on the MAIN PAGE where all the *online* users shown

please, help me out

[Zosia]

well ive found out =)))