> For the complete documentation index, see [llms.txt](https://docs.thousandeyes.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.thousandeyes.com/product-documentation/archived-documentation/permitted-content-types-for-page-load-tests.md).

# Archived - Permitted Content Types for Page Load Tests

When a web server responds to an HTTP request, typically the response contains a "Content-Type" field in the HTTP header. A ThousandEyes page load test requires the target of the test (the **URL** field of the configuration page) to have a content-type of either "text/html" or "application/xhtml". When saving a page load test's configuration, the ThousandEyes platform requests the URL and checks the response's content-type to ensure that the content-type is one of these values. If the target of the page load test does not have either of these values, the test configuration page displays an error upon attempting to save the configuration. For example, if the target is a JPEG image, the test configuration page displays the following error:

> ```
> URL's Content-Type: 'image/jpeg' is not allowed for this test type.
> It should be 'text/html' or 'application/xhtml' (web page)
> ```

The purpose of a page load test is to provide timings for loading a DOM object and the child objects. If you wish to time the loading of a single object, configure an HTTP server test instead. HTTP server tests are used to obtain the timings for targets such as multimedia files (images, video or audio), plain text, archive files or other files intended to be saved to storage rather than rendered in a browser. Additionally, using an HTTP server test benefits customers because HTTP server tests have a lower cost in terms of [unit consumption](https://docs.thousandeyes.com/product-documentation/user-management/usage-and-billing/how-unit-consumption-works) than page load tests.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.thousandeyes.com/product-documentation/archived-documentation/permitted-content-types-for-page-load-tests.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.