Javascript/Rails/JQuery应用中第三个debugger断点无法触发求助

Hey Chris, let's dig into why that third debugger in your $.getJSON success callback isn't triggering. Here are the most likely culprits and how to check them:

Common Causes & Fixes #

• The AJAX request failed entirely
  Your third debugger lives inside the .success() callback—if the $.getJSON call doesn't succeed (for any reason), this code never runs. To confirm:

  1. Open your browser's DevTools (F12) and go to the Network tab.
  2. Click the .loadCars button and look for the request matching your url.
  3. Check the status code (e.g., 404 if the Rails route is missing, 500 if there's a server error) and ensure the response is valid JSON.
     Pro tip: jQuery's .success() is deprecated—switch to .done() and add a .fail() handler to catch failures explicitly:

  $.getJSON(url)
    .done(function(data) {
      $('#cars').html("");
      debugger;
      // Finish your $.each implementation here
    })
    .fail(function(jqXHR, textStatus, errorThrown) {
      console.log("Request failed:", textStatus, errorThrown);
      debugger; // This will trigger if the request fails
    });
  

• Syntax error in your incomplete $.eac... code
  The snippet you shared cuts off at $.eac...—if this is a typo (like missing the h in $.each()) or incomplete syntax, the browser will throw an error before reaching the debugger. Check the Console tab in DevTools for any syntax error messages.

• Missing DOM element #cars
  While this won't stop the debugger from firing, if $('#cars') doesn't find any element, it might lead to unexpected behavior later. Double-check that your HTML has an element with id="cars".

• Request blocked by Rails filters
  If your Rails controller has a before_action (like authentication) that rejects the request, it'll return an error status instead of valid JSON, which skips the success callback. Check your Rails server logs for any clues about why the request is being rejected.

内容的提问来源于stack exchange，提问作者Chris