<!DOCTYPE html>
<html>
<body>
<p>Click the button to global search for a substring that contains a sequence of three to four digits.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var str = "100, 1000 or 10000?";
var patt1 = /\d{3,4}/g;
var result = str.match(patt1);
document.getElementById("demo").innerHTML = result;
}
</script>
</body>
</html>