Execute script after click in popup.html (chrome extension)

I wrote a demo for your need.

https://gist.github.com/greatghoul/8120275


alert.js

alert('hello ' + document.location.href);

background.js

// empty file, but needed

icon.png

icon

manifest.json

{
  "manifest_version": 2,

  "name": "Click to execute",
  "description": "Execute script after click in popup.html (chrome extension) http://stackoverflow.com/questions/20764517/execute-script-after-click-in-popup-html-chrome-extension.",
  "version": "1.0",

  "icons": {
    "48": "icon.png"
  },

  "permissions": [
    "tabs", "<all_urls>"
  ],

  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },

  "background": {
    "scripts": ["background.js"],
    "persistent": false
  }
}

popup.html

<!DOCTYPE html>
<html>
  <body style="width: 300px">
    Open <a href="http://stackoverflow.com" target="_blank">this page</a> and then 
    <button id="clickme">click me</button>
    <script type="text/javascript" src="popup.js"></script>
  </body>
</html>

popup.js

// var app = chrome.runtime.getBackgroundPage();

function hello() {
  chrome.tabs.executeScript({
    file: 'alert.js'
  }); 
}

document.getElementById('clickme').addEventListener('click', hello);

You can also use Messaging:

in popup.js

document.getElementById("clicked-btn").addEventListener("click", function(e) {
    chrome.runtime.sendMessage({'myPopupIsOpen': true});
});

in background.js

chrome.runtime.onMessage.addListener(function(message, sender) {
      if(!message.myPopupIsOpen) return;

      // Do your stuff
});

Not tested but should works, further informations about Messaging.