[alserio]

Thank you. I was looking at a generic way to pass configuration data to custom elements where I cannot know the shape in advance, since another dev can have different requirements. I support data attributes for simple types but i was wondering if allowing arbitraty json objects via other means could be feasible.

[hunter2_]

Since JSON is a subset of JavaScript, you can just use a script element, and including the json mime type certainly doesn't hurt:

    <script type="application/json" id="myJSONData">
      {
        "name": "John Doe",
        "age": 30
      }
    </script>

    <script>
      const data = JSON.parse(document.getElementById('myJSONData').textContent);
      console.log(data.name + " is " + data.age); // John Doe is 30
    </script>

Note: The JSON data must exist literally within the script element. If you try using a src attribute to request it from elsewhere, the response will not be available via textContent or any other mechanism [0], and at that point you just need to fetch/ajax/xhr it.

[0] https://stackoverflow.com/questions/17124713/read-response-o...

[lioeters]

About embedding JSON in a script tag, I recently read an article on the risk of a closing </script> tag within the JSON that could break it.

Safe JSON in script tags: How not to break a site - https://sirre.al/2025/08/06/safe-json-in-script-tags-how-not...

As with all untrusted content, depending on where the JSON string comes from, sanitizing the output is worth considering.