Question

I am doing some self learning about Patern Matching in Javascript.
I got a simple input text field in a HTML web page,
and I have done some Javascript to capture the string and check if there
are any strange characters other than numbers and characters in the string.
But I am not sure if it is correct.
Only numbers, characters or a mixture of numbers and characters are allowed.

var pattern = /^[a-z]+|[A-Z]+|[0-9]+$/;

And I have another question about Pattern Matching in Javascript,
what does the percentage symbol mean in Pattern matching.
For example:

var pattern = '/[A-Z0-9._%-]+@[A-Z0-9.-]+\.[A-Z]{2,4}/';

Answer 1

You can put multiple character ranges inside a [] class.

var pattern = /^[a-zA-Z0-9]+$/
//or 
var pattern = /^[a-z0-9]+$/i // <- using "case insensitive" modifier

Percentage symbol means percentage symbol will be matched, it has no special meaning inside a regular expression.