PHP按时间切换显示不同按钮功能异常及旧按钮显示问题求助

Let’s break down the likely culprits here and walk through actionable fixes step by step:

1. Time Zone Handling Inconsistencies (Root of Chrome’s Flakiness) #

Your code’s reliance on US Central Time is probably failing because it’s either using an unconfigured server time or client-side JavaScript (which is unreliable and user-dependent). That’s why Chrome behaves unpredictably.

• Fix Step: Force PHP to use Central Time explicitly with timezone-aware code. Replace any generic time checks with this:

  // Set timezone to US Central (America/Chicago)
  date_default_timezone_set('America/Chicago');
  
  // Get current hour in 24-hour format
  $currentHour = (int)date('H');
  
  // Define the target window: 12pm (12) to 2am (2)
  $isEveningWindow = ($currentHour >= 12) || ($currentHour < 2);
  
  // Render the correct button
  if ($isEveningWindow) {
      echo '<button class="evening-btn">Your Evening Button Text</button>';
  } else {
      echo '<button class="day-btn">Your Day Button Text</button>';
  }
  

  This ensures the time check always uses the correct timezone, not server defaults or client-side time.

2. Aggressive Browser Caching (Why IE/Firefox Show Old Buttons) #

The old button markup popping up has nothing to do with cookies—it’s browser caching storing outdated versions of your page.

• Fix Steps:
  • Add cache-busting headers to your PHP script to prevent browsers from saving old content:

    header("Cache-Control: no-cache, no-store, must-revalidate"); // HTTP 1.1
    header("Pragma: no-cache"); // HTTP 1.0
    header("Expires: 0"); // Proxy cache fix
    

  • If your site uses a CDN or server-side caching (like Apache mod_cache), flush those caches immediately.
  • For quick testing in IE/Firefox: Use Ctrl+Shift+R (hard refresh) to bypass cached content temporarily.

3. Leftover Client-Side JavaScript Conflicts #

Old, forgotten JS might be overriding your PHP-rendered buttons—especially if the site previously used client-side time checks.

• Check Step:
  • Open DevTools (F12), go to the Elements tab, and inspect the buttons. Watch if any JS modifies or replaces them after page load.
  • Search your codebase for any old time-based button logic and delete or disable it if it’s no longer needed.

4. Server Clock Misconfiguration #

Even with correct PHP timezone settings, if your web server’s system clock is wrong, it’ll throw off the time check.

• Verification Step:
  • Run this quick script to confirm the server’s Central Time output:

    date_default_timezone_set('America/Chicago');
    echo date('Y-m-d H:i:s T');
    

  • If the output doesn’t match current US Central Time, reach out to your hosting provider to correct the server’s system clock.

内容的提问来源于stack exchange，提问作者soulfrog