title: IBM BPM how to handle keypress events in Coach Views
body: <p>I am somewhat familiar with HTML, CSS and JavaScript and have written some small apps using Angular and Ionic. </p>
  
  <p>Now I am working with IBM BPM Coach Views and tries to make a simple Coach View 
  with an input field (bound to a string variable) and a button.</p>
  
  <p>I would like to have the button disabled (in BPM language: read only) as long as
  the field is empty, but when the user starts to type anything in the field, the button should become enabled. I have bound the visibility of the button to another string variable.</p>
  
  <p>I have searched around and it seems I cannot find any simple examples of controlling visibility based on keypress events in BPM.</p>
  
  <p>All I have seen are examples with Dojo components and Dijit widgets and currently that is a bit above my head. I would expect there must be some (relatively) simple way of doing it with some 20-40 lines of JavaScript in either the “Inline JavaScript” section or in one (or more) of the “Event Handlers” on the Behavior tab in the Coach View Designer in IBM BPM 8.5.6.
  (it opens in a browser window because my Coach View runs in a Client Side Human Service).</p>
  
  <p>Does anyone have such a simple example.</p>