title: Add a character at nth place in TextBox text
body: <p>I want to add a "." character at the 4th place inside textbox string.</p>
  
  <p>Like if the string is "1234567", it should become 123.4567
  Also i want to restrict decimal to 4 digits.</p>
  
  <p>Please held in JQuery.</p>
  
  <p>Edited:</p>
  
  <p>On entering numeric characters (for this i have implemented a check which allows numeric only), after 
  3 characters a "." should appear automatically.</p>