title: How to programmatically open a chrome extension popup window from background.html
body: <p>Thanks in advance!</p>
  
  <p>What I want to achieve is to open the popup window when a special tag is detected on a webpage by my extension. After searching for a while it seems like the popup can only be opened when user clicks the extension. Is it true? </p>
  
  <p>Or could I get the location of my extension's icon on browser? Maybe I could draw a window and display under the extension icon to make it looks just like the popup window.</p>