Java Script Validations in RESTful Ruby on Rails Form

We can validate ruby on rails form using java script.It is show in bellow example

java script function

function validate()
{
//validation code
if (valid)
return true
else
return false
}

ruby on rails form

<% form_for(@patient_details,:html=>{:onsubmit=>"return validate();"}) do |f| %>
<%= f.error_messages %>
#form

<%end%>