Weird behavior for adding "embed code" inside our classic pages and inside application pages

---

Deleted wrote:
Have you actually tried to insert script into the page? I remember my Sharepoint site would have this option available, but soon as I added the script tag to the box and hit Ok it would prompt me to a warning telling me I couldn't.

---

Deleted

thanks a lot for the advice. now i created a classic page >> add "Embed code" , i got this 2 results:-

1. Inside the embed code i added pure HTML element, as follow:-

<h1 unselectable="on">test</h1>

and i were able to save the page without any issue.

2. While if i try to add a script element inside the "Embed code" as follow:-

<h1 unselectable="on">test</h1>
<script>
alert("123");
</script>

i got this error:-

This HTML cannot be inserted because you don't have access to add scriptable Web Parts in this site. Please contact your administrator if you think you should have rights to do so.

so can i conclude that in my case i can add "embed code" web parts, but those "embed code" need to contain HTML only?

second question, so seem i do not have "custom scripts" enabled inside our communication site (since i was not able to add <script> tags inside the "embed code"). so can i enable the custom scripts for this communication site only, without having to affect the "custom scripts" settings inside other sites, or change the settings inside the sharepoint admin center site?