String pattern matching in Javascript

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开发者_如何学Python percentage symbol mean in Pattern matching. For example:

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

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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.

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% in that JavaScript regex doesn't have any special meaning 0 - it's just one more matching character.