i have one radio button "balance amt" of "balamt-tds" radio group and one textbox field "balance_amount" of "cserc_generate_ecf" datablock.

my doubt is:
1)if i choose radiobutton "balance amt" then only the textbox should be visible, otherwise it should not be visible.
2)The above code logic where i have to write, in which trigger like pre_text_item or when_mouse_click.

thank you.............