title: getting href onclick
body: <p>I am developing an extension for Mozilla Firefox. A main function is to get the URL that the user is visiting and process it later. I tried the following Javascript code:</p>
  
  <pre><code>window.onload = function(){
    alert(document.referrer);
  }
  </code></pre>
  
  <p>That didnt work so I tried to inject an <code>onclick</code> event to every link using this:</p>
  
  <pre><code>window.onload = function(){ 
      var links = document.links;
      for(var i=0;i&lt;links.length;++i){  
          links[i].onclick = show_href();
      }
  }
  
  function show_href(){
      alert(this.href);    
  }
  </code></pre>
  
  <p>But that also doesnt work. Any other approach?</p>