Javascript Link Protector

Question

Ola would like to know how I can change the code below link protection in the following precise way that in case it releases the download link if you click on some advertising area within a DIV and that has to apply this function in several div through the use of ID.

I also need a message like "Link being generated wait time or click on one of the advertisements to release the link"

Obs: Time and where the count will appear.

So that use ID in them to identify the DIV’s that have the advertisements and when they are clicked is released the link Download the code I have only applies a chronometer no more releases the links, someone can help me ?

<script>
var tempo = 10;

window.onload = function () { 
  contagem();
} 

function contagem() {
 if(tempo>0) {
  var span = document.getElementById('tempo_espera');
  span.innerHTML = tempo;
  tempo--;
  setTimeout("contagem()",1000);
 }
 else {
var div = document.getElementById('subs'); 

    div.innerHTML = '<a id="down" href="downloads.php?protetorpage=multiplo_download&tipo=video&action=download&id=2&url=url"><b>BAIXAR</b><br />PELO MEDIAFIRE</a>';

 }
}
</script>

Someone could help me with this ?