Help Pleas Help

Help Pleas Help

i use jQuery in Joomla Cms (in a custom module)
but events like "on click ..." does not work

this works
  1. $('.mydiv').css('padding','100px');
this does NOT work
  1. $('.mydiv').on('click',function(){$('.mydiv').css('padding','100px');});
wat do you guse the probable reason is ?
tx