Display current URL in a chrome extension

Maybe this is what your looking for....

chrome.tabs.query({'active': true, 'windowId': chrome.windows.WINDOW_ID_CURRENT},
   function(tabs){
      alert(tabs[0].url);
   }
);

And the tabs permission needs to be set in the manifest...

manifest.json

"permissions": [ 
  "tabs"
]

I had the same issue. I wrote this extension to display the current URL user is browsing now in the popup.

manifest.js

"permissions": [ 
  "tabs"
]

popup.js

function getCurrentTabUrl(callback) {  
  var queryInfo = {
    active: true, 
    currentWindow: true
  };

  chrome.tabs.query(queryInfo, function(tabs) {
    var tab = tabs[0]; 
    var url = tab.url;
    callback(url);
  });
}

function renderURL(statusText) {
  document.getElementById('status').textContent = statusText;
}

document.addEventListener('DOMContentLoaded', function() {
  getCurrentTabUrl(function(url) {
    renderURL(url); 
  });
});