tinymce remove span when submitting prism.js

Question

So far when I open prism.js in tinymce text editor, it appears fine, it highlights the code, of course because when I inspect, the tag <span> exist inside the <pre> tag. The problem is, when submitted, the <span> tags don't follow any more. They just disappear. What's wrong? Is it famous unsolved problem of prism.js as tinymce plugin? Or am I missing something? I just need the <span> to be there when submitted. That's all.

Please help. Thanks in advance.

/------------- for clarity, here is the plugin code ---------------------/

tinymce.init({
    selector: '.content_textarea',
    plugins: 'advlist autolink link image lists charmap print preview codesample emoticons',
    toolbar: 'undo redo | styleselect | bold italic | numlist bullist | codesample | link image | emoticons',
    link_class_list: [
        {title: 'None', value: ''},
        {title: 'Demo', value: 'btn demo'},
        {title: 'Download', value: 'btn download'}
    ],
    codesample_languages: [
        {text: 'HTML/XML', value: 'markup'},
        {text: 'JavaScript', value: 'javascript'},
        {text: 'CSS', value: 'css'},
        {text: 'PHP', value: 'php'},
        {text: 'Ruby', value: 'ruby'},
        {text: 'Python', value: 'python'},
        {text: 'Java', value: 'java'},
        {text: 'C', value: 'c'},
        {text: 'C#', value: 'csharp'},
        {text: 'C++', value: 'cpp'}
    ],
    valid_elements: "*[*]",
    image_dimensions: false,

    image_title: true, 
    image_caption: true,
    // enable automatic uploads of images represented by blob or data URIs
    automatic_uploads: true,
    // URL of our upload handler (for more details check: https://www.tinymce.com/docs/configure/file-image-upload/#images_upload_url)
    images_upload_url: base_url()+'admin_crud/img-upload-tinymce',
    // here we add custom filepicker only to Image dialog
    file_picker_types: 'image', 
    // and here's our custom image picker
    file_picker_callback: function(cb, value, meta) {
        var input = document.createElement('input');
        input.setAttribute('type', 'file');
        input.setAttribute('accept', 'image/*');

        // Note: In modern browsers input[type="file"] is functional without 
        // even adding it to the DOM, but that might not be the case in some older
        // or quirky browsers like IE, so you might want to add it to the DOM
        // just in case, and visually hide it. And do not forget do remove it
        // once you do not need it anymore.

        input.onchange = function() {
          var file = this.files[0];
          var orig_filename = this.files[0].name;
          orig_filename = remove_ext(orig_filename);

          // Note: Now we need to register the blob in TinyMCEs image blob
          // registry. In the next release this part hopefully won't be
          // necessary, as we are looking to handle it internally.
          var id = orig_filename + (new Date()).getTime();
          var blobCache = tinymce.activeEditor.editorUpload.blobCache;
          var blobInfo = blobCache.create(id, file);
          blobCache.add(blobInfo);

          // call the callback and populate the Title field with the file name
          cb(blobInfo.blobUri(), { title: remove_ext(file.name) });
        };

        input.click();
    }
});

Answer 1

Those tags are added by Prism. TinyMCE calls Prism and when you add, edit or view your content inside of TinyMCE you will see the code highlighting. Viewing outside of TinyMCE results in not seeing the code highlights, this is because Prism has not been called.

In order for your code to look like what you saw inside of TinyMCE, you need to add

 Prism.highlightAll() 

or a variation of it depending on your use case on your page that does not call TinyMCE. See here: https://prismjs.com/extending.html#api