Fix javascript snippet injection doc (#14333)

laurit · web-flow · commit 4efd3d263bd6 · 2025-07-28T10:36:47.000-07:00
diff --git a/docs/advanced-configuration-options.md b/docs/advanced-configuration-options.md
@@ -39,19 +39,19 @@ this option if your application relies on security manager to run untrusted code
 
 ## JavaScript snippet injection
 
-This experimental feature allows you to inject JavaScript code into HTML responses from servlet applications. The agent will look for the `</head>` tag in HTML responses, and inject the configured JavaScript snippet before the closing `</head>` tag.
+This experimental feature allows you to inject JavaScript code into HTML responses from servlet applications. The agent will look for the `<head>` tag in HTML responses, and inject the configured JavaScript snippet after it.
 
 This feature is designed for integrating client-side monitoring.
 We plan to integrate OpenTelemetry's own client-side monitoring solution by default once it's available
 (see the [browser instrumentation proposal](https://github.com/open-telemetry/community/blob/main/projects/browser-phase-1.md)).
 
-| System property                      | Environment variable                 | Purpose                                                                                                                                                                                                                                                              |
-|--------------------------------------|--------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| otel.experimental.javascript-snippet | OTEL_EXPERIMENTAL_JAVASCRIPT_SNIPPET | JavaScript code to inject into HTML responses before the closing `</head>` tag. The value should be a complete JavaScript snippet including `<script>` tags if needed, e.g. `-Dotel.experimental.javascript-snippet="<script>console.log('Hello world!');</script>"` |
+| System property                      | Environment variable                 | Purpose                                                                                                                                                                                                                                                                                      |
+|--------------------------------------|--------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| otel.experimental.javascript-snippet | OTEL_EXPERIMENTAL_JAVASCRIPT_SNIPPET | Experimental setting to inject a JavaScript snippet into HTML responses after the opening `<head>` tag. The value should be a complete JavaScript snippet including `<script>` tags if needed, e.g. `-Dotel.experimental.javascript-snippet="<script>console.log('Hello world!');</script>"` |
 
 **Important notes:**
 
 - This only works with servlet-based applications currently
-- The snippet is injected only into HTML responses that contain a `</head>` tag
+- The snippet is injected only into HTML responses that contain a `<head>` tag
 - The agent will attempt to preserve the original character encoding of the response
 - If the response already has a `Content-Length` header, it will be updated to reflect the additional content
