Match any string containing at most one p.

To match any string containing zero or one p’s with JavaScript RegExp, use the p? Quantifier.

Example

You can try to run the following code to match any string containing zero or one p. Here p is considered a number of occurrences −

<html>
   <head>
      <title>JavaScript Regular Expression</title>
   </head>

   <body>
      <script>
         var myStr = "Welcome 1, 100, 10000, 10000";
         var reg = /10?/g;
         var match = myStr.match(reg);
         
         document.write(match);
      </script>
   </body>
</html>