button_to_function

Hi   I have <%= button_to_function "Save As Resolved",{'class' => 'itilbuttonlink1'} do |page|     page.visual_effect :BlindDown, 'here_call_sd_resolution_div' end %>

Here can I use :before clause as in the case of link_to_remote..What I am trying is before the div 'here_call_sd_resolution_div' is shown(by default its visibility hidden), call a javascript to check a particular field is empty or not..And I want the div be shown only that field(say for example a text field) is non empty.How can I do this?

Thanks in advance Sijo