title: filteredtextboxextender validchars regular expression asp.net
body: <p>i need to validate Mobile number so i user ajax filteredtextboxextender </p>
  
  <p>like below code </p>
  
  <pre><code>     &lt;ajax:FilteredTextBoxExtender ID="FilteredTextBoxExtender1" TargetControlID="Mobile_Code" ValidChars="[+]{0,1}" FilterType="Custom,Numbers" runat="server"&gt;&lt;/ajax:FilteredTextBoxExtender&gt;
  </code></pre>
  
  <p>but its allowing + for 5 times so i tried in regular expression .its not working....
  i need it should allow only One + e.g (+9600114477) </p>
  
  <p>where i made error ,thank you </p>