Links Protector in JavaScript

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

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

Note: Time and where the count will appear.

So that I use ID in them to identify the DIV's that have the advertisements and when they are clicked the release link is released Download the code that I have only applies a timer but does not release the links, can anyone 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>

Can anyone help me with this?