In addition to the previous post, it is also possible to disable that feature.
Just go to the Sitecore.config to the following entry
<!-- HTML EDITOR REMOVE SCRIPTS
If true, the rich text editor removes script tags and inline scripts from RTE field values before saving. Setting the value to true reduces the potential for cross-site scripting and other script-related issues.
Default value: true
<setting name="HtmlEditor.RemoveScripts" value="true" />
and set it to false.
But in general I agree, that this is not recommended, but if other apporaches wont work, this would also be an option.