Question

This is to check only digits in a string.. It’s returning true when I expected to return me a false..
How can I fix this and why it’s returning me a true?

  <script type="text/javascript">
      function test()
var str2 ="s123s";
var reg3 =/\d/;
alert(reg3.test(str2));
}
</script>

Answer 1

You regex is testing if there is one digit in the string — and not if the string contains only digits.

If you what to check for a string that

• starts with a digit,
• contains one or more digits — and nothing else,
• and end with a digit,

you should change your regex to something like this :

/^\d+$/