Prototype Not Defined When Accessing Children On Creation Of Custom-tag

__What I am trying todo____ Right now I am working with custom HTML5 tags. I am trying to create a tab-control element that is easy to set up. Todo this I create a parent element

Solution 1:

__ Solved __

All I had todo was add a link-tag inside the tab-set and have the tab-elements load it's containing style-class. I guess making the tab-elements have a css-class is somehow provoking Chrome to load their prototypes 'prematurely'.