<script type="text/javascript">       
    divWeHave = document.getElementsByTagName('DIV');       
    replacement = new Array (       
    'Первая замена',       
    'вторая',       
    'третья и т.д.'       
    );       

    numer = 0;       

    for(i=0;i<divWeHave.length;i++){       
    if(divWeHave[i].className == 'forumModer'){       
    divWeHave[i].innerHTML = replacement[numer]+divWeHave[i].innerHTML.slice(16);       
    numer++;       
    }       
    }       
    </script>