title: Regular expression for decimal number
body: <p>I need to validate a <code>textbox</code> input and can only allow decimal inputs like: <code>X,XXX</code> (only one digit before decimal sign and a precision of 3).</p>
  
  <p>I'm using C# and try this <code>^[0-9]+(\.[0-9]{1,2})?$</code>?</p>