Adding new sliders via JS

[insideru]

Hi,

I'm attempting to add new sliders via JS, but initializing by class messes up the whole page, while initializing by id disables the previously created instances.

I'm sure its something easy, i just can't figure it out on my own :(

Here is what i'm talking about:
https://jsfiddle.net/insideru/6y2kw57m/3/