Great question—this boils down to how development-focused servers are purpose-built for active coding workflows, versus general-purpose servers like IIS that lean toward production-ready behavior by default. Let’s break it down:

1. Dev Servers Automatically Block Caching Out of the Box #

Tools like webpack-dev-server, gulp’s dev server, or live-server are designed to eliminate caching headaches during development. They do this in two key ways:

• Content Hashed Filenames: Every time you edit your JS/CSS, the server generates a new file with a unique hash in the name (e.g., app.7f9d2b.js instead of app.js). Since the filename changes, the browser treats it as an entirely new resource and never uses an old cached version.
• Strict Cache-Control Headers: These servers send response headers like Cache-Control: no-cache, no-store, must-revalidate and Pragma: no-cache with every static asset request. This tells the browser to never store the resource locally, so it always asks the server for the latest version.
• Hot Reloading: Many dev servers also include hot module replacement (HMR), which pushes updates directly to the browser when files change—you don’t even need to refresh, so caching never becomes an issue.

2. IIS’s "Prevent All Caching" Setting Doesn’t Override Existing Browser Cache #

When you set IIS to "prevent all caching," it configures the server to send no-cache headers for future requests. However, if your browser already cached the JS file before you changed this setting, it will still use the local cached copy until that cache expires (or you force it to refresh).

Chrome’s "Disable cache" option in the Network tab bypasses this entirely—it tells the browser to ignore any local cached resources and fetch everything fresh from the server every time you reload. This is a temporary fix for testing, but dev servers handle this automatically so you never have to remember to toggle it.

3. IIS is Optimized for Production, Not Development #

Unlike dev servers, IIS is a general-purpose server built to handle production traffic efficiently. By default, it’s tuned to encourage caching (to reduce server load and improve performance). Even when you disable server-side caching, the browser’s own caching rules still apply unless explicitly overridden by the server’s response headers—and IIS might not set those headers as aggressively as a dev server does for every request.

内容的提问来源于stack exchange，提问作者Robert K