Select textbox from multiple css class.

Hi

I am having following  jquery
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which is used to set focus to next textbox when hit enter button. but it selected only textbox from  classfirst css class i want some modification in the same query which is i want all the textbox from classsecond, classthird, classfourth along with class first.

i am not getting idea how can i achieve this.


please help me to get this result.

Thanks in Advance.