The html that i am pasting in source of Tinymce contains a javascript function. But that function never executes when the content is loaded in Tinymce.
For example it should an alert message like an example below. But original content is to hide loader when page loads completes. But the loader never gets hide because the javascript is not executing.
Following is the example code:
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<h1>Some content</h1>
<script>
alert('some alert');
</script>
</body>
</html>
TinyMCE does not allow <script> tags by default due to security concerns. If you are sure they should be allowed in your implementation, you can use the extended_valid_elements option.
I've created a fiddle that demonstrates how it can be done: https://fiddle.tiny.cloud/5Shaab