However, it also causes trouble when you try to insert something from a third party that you trust. Such as Maps, Youtube or Charts...
This article will show you how to insert advanced codes into articles without losing them when saving. Please make sure you know what codes you are going to add.
1. First, you need to grant permissions to the user group that can use these tags.
At the admin page, go to System > Global Configuration > Text Filtering, select the user group. If you are an administrator, the group will be Super User. Select Filter Type as No Filtering.
2. Go to Extensions > Plugins > Editor - TinyMCE > Set Use Joomla Text Filter is Yes.
3. Go to the article to add code, click Toogle Editor button. Then paste the code to add and save the article.
In case you are using another editor, you should contact their developer to resolve it. Alternatively, you can also use the Custom HTML module to insert these codes.