To match any string containing a sequence of N p’s with JavaScript RegExp, use the p{N} Quantifier.
Example
You can try to run the following code to match any string containing a sequence of N p’s −
<html>
<head>
<title>JavaScript Regular Expression</title>
</head>
<body>
<script>
var myStr = "Welcome 1, 100, 10000, 1000";
var reg = /\d{3}/g;
var match = myStr.match(reg);
document.write(match);
</script>
</body>
</html>