Stop index change on focus using scroll keys

I'm trying when I navigate using keyup and keydown on dropdownlist, the it focus on the next element but change the index of previous dropdown. I need to stop it.

Link to file:

Kindly check it source code: http://69.175.126.242/~develope/younussal/test/开发者_开发百科test.htm

Actually I want to stop keyup and keydown indexing changing functionality on <select> element.