Fixing SyntaxError: Unexpected token < in JSON at position 0
The error message "SyntaxError: Unexpected token < in JSON at position 0" is commonly caused by trying to parse HTML as JSON. This can happen when an AJAX request is made to a server that returns HTML instead of JSON. In this article, we will discuss how to fix this error and avoid it in the future.
What is JSON?
Fixing the Error
To fix the "SyntaxError: Unexpected token < in JSON at position 0" error, you need to make sure that the server is returning valid JSON. Here are a few things you can try:
Check the server response
The first thing you should do is check the response from the server. Open your web browser's developer console and look at the network tab. Find the request that is causing the error and check the response. If it is HTML instead of JSON, then you have found the cause of the error.
Ensure the server is returning proper JSON
If the server is returning HTML instead of JSON, you need to modify the server to return the correct response. Make sure that the server is returning proper JSON with the correct MIME type, application/json.
Check the AJAX request
If the server is returning valid JSON, then the problem may be with the AJAX request. Check the AJAX request to make sure that the dataType is set to "json". If it is not set correctly, then the response may not be parsed as JSON.
The "SyntaxError: Unexpected token < in JSON at position 0" error can be frustrating, but it is easy to fix once you know the cause. By ensuring that the server is returning valid JSON and that the AJAX request is set up correctly, you can avoid this error in the future. Remember to always check the response from the server and make sure that it is what you are expecting.