title: How should a browser extension "capture" all GET and POSTs to a specific URL?
body: <p>I want my extension to capture, and inject custom behavior for any GET or POST to a specific URL. </p>
  
  <p>Access to these URLs can be done via </p>
  
  <ul>
  <li>A mouse click</li>
  <li>Javascript not written by me</li>
  <li>Perhaps another extension/plugin</li>
  </ul>
  
  <p>I will know, however, the FORM POST/GET parameter names (not values).  When this occurs I'll create a security dialog of some kind.</p>
  
  <p><strong>Question</strong></p>
  
  <ul>
  <li>How can I capture GET/POST events in a browser extension?</li>
  </ul>
  
  <hr>
  
  <p>Documentation for plugins it difficult to find on some browsers , and I need to run compiled Mono/.NET code on OS X and PC, so if I abandon the plugin approach I may leverage <a href="https://developer.apple.com/library/content/documentation/Tools/Conceptual/SafariExtensionGuide/CommunicatingwithyourOSXApplication/CommunicatingwithyourOSXApplication.html#//apple_ref/doc/uid/TP40009977-CH23-SW4" rel="nofollow noreferrer">Safari Extension Companions</a>, <a href="https://blog.chromium.org/2013/10/connecting-chrome-apps-and-extensions.html" rel="nofollow noreferrer">Chrome Native Messaging API</a>, or the equivalent in Firefox</p>
  
  <p>Due to compatibility issues with most sites, I don't want to create a dependency on a specific version of JQuery, in case that might somehow mess up the source website. </p>