CODEWITHSUNDEEP
javascriptregex
Tim Zhukov-Khovanskiy
Tim Zhukov-Khovanskiy

Reputation: 500

Length of regex expression with specific values

I have a javascript regex against a text area in an html form. Here's the regex:

    regex = /[EePp]+/

I would like to also use the regex to check the length of the string in the text area and to have it to be limited to a single character.

I tried

    regex = /[EePp]{1}/

And it validates regex to only those characters, but still allows strings of more than one character in the text area:

    <input type='text' onkeypress='validate(event)'>

Is it possible to do that through the regex?

Upvotes: 1

Views: 81

Answers (1)

DWright
DWright

Reputation: 9500

If you add anchors, ^ and $ at the start and end of your regex, this will limit it to matching only the pattern and nothing else against the full extent of what is being searched.

So, /^[EePp]{1}$/ -- That says [EePP] at the very beginning of what is being searched,^, and there is nothing between it and the end, $, of what is being searched.

Turns out that in this case you don't need the {1}, because the anchors are telling it exactly how far the match extends. So:

/^[EePp]$/

should do it.

Upvotes: 2

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