The other day I was trying to run Ajax with Rails and a very simple pop-up invocation started failing when I used it with prototype.js. Basically I wanted that when a link object is clicked, it pops up a message from the browser using Ajax. Essentially <OnSuccess> was intended to create this pop-up which was not appearing. So I changed <OnSuccess> to <OnFailure> to figure out the reason of failure and discovered the error [ActionController::InvalidAuthenticityToken] was causing the problem. This was strange since the non prototype.js counterpart code was working….. Read More