title: Get the active tab url in crossrider
body: <p>I came to know that crossrider.com is helping us to develop extension for different browsers, while keeping the same code. </p>
  
  <p>I have two questions</p>
  
  <p>Question 1:</p>
  
  <p>After going through docs and libraries in crossrider, I still wonder how to get the active tab url.</p>
  
  <p>Question 2:</p>
  
  <p>I also need to open a popup after clicking toolbar icon, similar to google chrome extension. 
  I came across crossrider siderbar plugin. But, I am unable to change the url for sidebar dynamically.
  Do we have any other crossrider plugins which opens like an popup ?</p>