title: Server side validation in ServiceNow platform
body: <p>I am writing validation scripts in ServiceNow platform. I need to validate form data on record producers and service catalog items. How do I properly validate form data on <strong>the server side without being called by a client script</strong>?
  I already have a catalog client script working to call a serverside ajax function in a script include.</p>
  
  <p>What if the client is disabled? Then the server script is not invoked and the data goes in without validation. I learned in school that the best technique to validate forms when building web applications is to first validate on the client and then on the server. I have done this many times with javascript (client side) and PHP (server side). The PHP processes the validation on the server when it receives the user entry and does not need to be invoked directly by the client side. Client scripts can be disabled in the browser. This is why separate server-side validation should occur before the data is accepted.</p>
  
  <p>How to achieve this in ServiceNow platform? I was thinking of using a Script Include called by a Business Rule.</p>
  
  <p>Are there any simpler ways to complete this? Does anyone have any examples?</p>