JS Bin// source http://jsbin.com/xemicefoxi

Chrome Extension Example.js

// Chrome extension button / popup / requester
chrome.tabs.getSelected(null, function(tab) {
  chrome.tabs.sendRequest(
    tab.id, // id of the tab to send a request to.
    {method: "getHighlighted", name: "John"}, // data to send to the tab
    function(response) { // function to execute when the tab responds.
    if (response.method == 'getHighlighted') {
      chrome.setClipboard(response.data); // Something like this.
      // response.data contains our highlighted text.
    }
    else if (response.method == 'someOtherMethod') {
      // do something else if this is a response to another method.
    }
  });
});



// Content Script / Responder
// Request listener goes here.
// Gets installed as part of the extension and runs in the background
chrome.extension.onRequest.addListener(function(request, sender, response) {
  // This is a request listener.
  // Only act if the request method is actually what we want to respond to.
  if (request.method == "getHighlighted") {
    // Send a response to the request
    sendResponse({method: request.method, data: document.all[0].getHighlightedText()});
  }
});

chrome.extension.onRequest.addListener(function(request, sender, response) {
  // This is a totally different request listener.
});