simple bsp page problem

hi

I am trying to show the increament of a variable on bsp page by clicking a button. I am increamenting my variable in OnInputProcess() the code is :

<code>

data: in type I.

in = navigation->get_parameter( name = 'index').

in = in + 1.

navigation->set_parameter( name = 'index' value = in ).

</code>

I have defined 'index' as auto page attribute of type 'I'.

but I could not see the changed value of the valriable in browser on clicking the button.

can you please help me on this.

regards

Ashutosh