jQuery freshman needs some feedback

jQuery freshman needs some feedback

Hey guys,

I’m starting to create my very first German jQuery Mobile web-app (Only Web-App - I’m currently not planning to use Cordova etc.). Therefore I started with the user login, password-reset and registration. Now it is time to ask some veterans for some feedback.

Questions I have: 

How can I improve the attached code, especially in JavaScript/jQuery because I’m completely fresh to this?

Do I use something twice or do I using crazy stuff while there are better solutions?  

I appreciate your feedback.