zend form using dojo (ajax) to check yhe checkbox and where to write the javascript codes?

Question

I have made a default form using Zend Framework which is working well. i need to use any kind of ajax in the form may be dojo which comes with Zend. I dono how to use these form elements and how to call them. like when i click on a radio button called yes,open an textbox or change data. any example ?