Javascript: indexOf with Regular Expression

Question

How can I check whether the page url contains a '#' character plus some random digits

e.g. www.google.de/#1234

if( window.location.href.indexOf('#') > 0 ){
  alert('true');
}

Does indexOf support Regular Expressions?

Why do you need to know the index of it? Just use the .match() function to test if the regexp matches? — Barmar
– Barmar, Commented Jun 1, 2016 at 15:16

Andreas Louv · Accepted Answer · 2016-06-01 15:20:03Z

21

Use String.prototype.search to get the index of a regex:

'https://example.com/#1234'.search(/#\d+$/); // 20

And RegExp.prototype.test if used for boolean checks:

/#\d+$/.test('https://example.com/#1234'); // true

The regex used for these examples are /#\d+$/ which will match literal # followed by 1 or more digits at the end of the string.

As pointed out in the comments you might just want to check location.hash:

/^#\d+$/.test(location.hash);

/^#\d+$/ will match a hash that contains 1 or more digits and nothing else.

answered Jun 1, 2016 at 15:17

Andreas Louv

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1 Comment

Thank you very much for the detailed explanation.