Filter Inputs and Select Values

Suite 7.0/6.0/5.0 and Optimus Suite 5.0
#1

I added some filters in a grid:

mygrid.attachHeader("#text_filter,#text_filter,#select_filter");

They are working fine but when I return from a page the input box and select in the header are keeping their value but when I am trying to get their values through: mygrid.getFilterElement(1) the method returns null.

How can I get the values of the filter inputs and selects in the header of a grid when I returning from other page?

Thanks