how to add active class element when clicked

Question

My menu is :

 <div class="collapse navbar-collapse bs-navbar-collapse" role="navigation">
            
<ul class="nav navbar-nav">
    
 

    <li class="active">
        <a href="default.asp" id="home">
        ANA SAYFA
        </a>
    </li>
 
    
    <li class=" dropdown">
        <a href="/kurumsal/"  class="dropdown-toggle"
        data-toggle="dropdown">
        KURUMSAL
        <b class="caret"></b>
        </a>
        <ul class="dropdown-menu" aria-labelledby="drop2" role="menu">
            
            <li><a href="hakkimizda.asp">Hakkımızda</a></li>
            
            <li><a href="kadromuz.asp">Kadromuz</a></li>
            
            <li><a href="hizmet-anlayisimiz.asp">Hizmet Anlayışımız</a></li>
            
            <li><a href="isletme-fotograflari.asp">İşletme Fotoğrafları</a></li>
            
            <li><a href="referanslar.asp">Referanslar</a></li>
            
            <li><a href="fuar-fotograflari.asp">Fuar Fotoğrafları</a></li>
            
            <li><a href="sozlesme-fotograflari.asp">Sözleşme Fotoğrafları</a></li>
            
        </ul>
    </li>
    
    
    
    <li class=" dropdown">
        <a href="/urunler/"  class="dropdown-toggle"
        data-toggle="dropdown">
        ÜRÜNLER
        <b class="caret"></b>
        </a>
        <ul class="dropdown-menu" aria-labelledby="drop2" role="menu">
             <%
set urn=server.createobject("adodb.recordset")
urn.open "kategori order by sira asc",cms,1,3
%>
 <% do while not urn.eof %>
            <li><a href="urunler.asp?kategori=<%=urn("id")%>"><%=urn("kategori")%></a></li>
   
   <% 
urn.movenext
loop
%>

<%
urn.close
set urn = Nothing
%>
            
        </ul>
    </li>
    
    
    
    <li class="">
        <a href="basinda-schtec.asp" id="press" >
        BASINDA SCHTEC
        </a>
    </li>
    
    
    
    <li class="">
        <a href="satis-sonrasi.asp"  id="sell" >
        SATIŞ SONRASI
        </a>
    </li>
    
    
    
    <li class="">
        <a href="iletisim.asp" id="contact" >
        İLETİŞİM
        </a>
    </li>
    
    
</ul>
            <ul class="nav navbar-nav navbar-right">
                <li class="active"><a href="default.asp">TR</a></li>
                <li><a href="en">EN</a></li>
  <li><a href="ru">RU</a></li>
            </ul>
             <ul class="nav navbar-nav navbar-left">
                <li><a href="http://www.facebook.com/schtec" target="_blank"><i style="color:#fff;font-size:18px" class="fa fa-facebook-square"></i></a></li>
            </ul>


            <!--<form class="navbar-form navbar-right" role="search" action="/search/" method="get">-->
                <!--<div class="form-group">-->
                    <!--<input name="q" type="text" class="form-control input-sm" placeholder="Arama">-->
                <!--</div>-->
                <!--<button type="submit" class="btn btn-sm"><i class="glyphicon glyphicon-search"></i></button>-->
            <!--</form>-->
        </div>

And I want to learn how to add active class "li" element when clicked

for example I clicked İLETİŞİM when I go to iletisim.asp only

<li class="active">
            <a href="iletisim.asp" id="contact" >
            İLETİŞİM
            </a>
        </li>

the others class= ""