Extension Popup Click Events Fail: Resolving Content Security Policy Violation

Error Description

In a Chrome extension, click events on both the extension icon and a button within the popup page are not generating the expected response of incrementing a JavaScript variable.

Inspecting the Root Cause

To debug the issue, inspect the popup page and examine the console logs. The error message likely indicates a Content Security Policy (CSP) violation:

Refused to execute inline script because it violates the following Content Security Policy directive: "script-src 'self' chrome-extension-resource:".

Compromised CSP Compliance

Inline scripts within the HTML page violate the default CSP. Inline JavaScript is not permitted under this policy.

Solution: Isolating JavaScript

To resolve the issue, eliminate all inline JavaScript from the HTML file and place it in a separate JavaScript file.

Revised Code Structure

hello.html (Popup Page)

popup.js

var a = 0;
function count() {
  a  ;
  document.getElementById('demo').textContent = a;
}
document.getElementById('do-count').onclick = count;

Notes

• Replace innerHTML with textContent when changing text to mitigate potential XSS vulnerabilities.
• This solution ensures compliance with CSP, enabling proper script execution and click event handling.