title: Regular expression for a decimal with a max of 2 digits before decimal point
body: <p>I am trying to find a regular expression that works for a decimal with a max of 2 digits before the decimal point and 2 digits after the decimal point.  The decimal point and decimal places are optional.  So these values would be accepted :</p>
  
  <pre><code>90
  5.4
  45.21
  0.5
  0
  </code></pre>
  
  <p>And the would be  rejected :</p>
  
  <pre><code>100
  105.56
  05.6
  55.543
  78.
  </code></pre>
  
  <p>Can any regex gurus help?</p>