This is generated by the Joomla Content Email Cloaking plugin.
If your email field is filled with javascript code that breaks the form's layout and makes it unusable , here is what you should do:
1.
First method: Disable the plugin completely. You can do this by going to Extensions > Plugin Manager and disabling the Content Email Cloaking. This will disable the plugin for your entire site.
2.
Second method: Because this plugin is used against spam bots that are scanning for email addresses you can leave it ON, but disable it on certain content pages, where the form is embedded (using the
mos_rsform plugin). Before placing the form placeholder (for example {rsform 1}, where "1" is the form's id you wish to display) just add {emailcloak=off}. You can re-enable email cloaking for portions of your article by typing {emailcloak=on} before any email address.