Adding onclick event to image_tag in Rails 4

I am trying to add a onclick event to a image_tag in Rails 4. On click I want to call a function send() . This is what I am trying to do,

 <%=image_tag("send.png",:click=> send)%>

This doesnt work and im not using jquery, only pure javascript. I think :click works in Rails 3. Does anyone know the click event syntax in Rails 4

Thanks