title: GWT TextBox Regex
body: <p>I am using GWT textBox and i want it to allow only alpha numeric characters.Is there any example somewhere where i can use the RegExp which is provided in GWT 2.1?</p>
  
  <p>I would like to apply a regex for example <code>^[a-zA-Z0-9_]*$</code> .Please provide example code for making this working.Also i cannot use a third party library like the GWT-VL or something like that.</p>
  
  <p>I am using GWT 2.1.</p>
  
  <p>Thanks</p>