Alphanumeric, dash and underscore but no spaces regular expression check JavaScript

Alphanumeric, dash and underscore but no spaces regular expression check JavaScript

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Trying to check input against a regular expression.

The field should only allow alphanumeric characters, dashes and underscores and should NOT allow spaces.

However, the code below allows spaces.

What am I missing?

var regexp = /^[a-zA-Z0-9\-\_]$/;
var check = "checkme";
if (check.search(regexp) == -1)
    { alert('invalid'); }
else
    { alert('valid'); }

However, the code below allows spaces.

No, it doesn't. However, it will only match on input with a length of 1. For inputs with a length greater than or equal to 1, you need a + following the character class:

var regexp = /^[a-zA-Z0-9-_]+$/;
var check = "checkme";
if (check.search(regexp) === -1)
    { alert('invalid'); }
else
    { alert('valid'); }

Note that neither the - (in this instance) nor the _ need escaping.

[Solved] Regex pattern for alphanumeric, hyphen and underscore , Try this: Hide Copy Code. ^[a-zA-Z\d-_]+$ Read more: The 30 Minute Regex Tutorial[^]. Alphanumeric, dash and underscore but no spaces regular expression check JavaScript 1 Regular expression that accepts alphanumeric , non consecutive dash and non consecutive white space


You shouldn't use String.match but RegExp.prototype.test (i.e. /abc/.test("abcd")) instead of String.search() if you're only interested in a boolean value. You also need to repeat your character class as explained in the answer by Andy E:

var regexp = /^[a-zA-Z0-9-_]+$/;

What Are Alphanumeric Characters?, ( – ), apostrophe ( ' ), and period ( . ) TAGs: JavaScript, Regular Expressions, Password TextBox, TextBox Here Mudassar Ahmed Khan has explained with an example, how to allow only AlphaNumeric (Letters or Numbers), Underscore in Username and it must have length of 3 to 10 characters using JavaScript.


Got stupid error. So post here, if anyone find it useful

  1. -\._ - means hyphen, dot and underscore
  2. \.-_ - means all signs in range from dot to underscore

Regular expression examples, immediately following the alphanumeric string matched by the preceding brackets. The . (period) matches any character (a wildcard). Trying to check input against a regular expression. The field should only allow alphanumeric characters, dashes and underscores and should NOT allow spaces. However, the code below allows spaces.


This syntax is a little more concise than the answers that have been posted to this point and achieves the same result:

let regex = /^[\w-]+$/;

Including a hyphen in a regex character bracket?, actually causes it to not require escaping, as it then can't be part of a range, however you might still want to get into the habit of always escaping it.) Regular Expression to Matches Alphanumeric characters with space alone. https://digitalfortress.tech/tricks/top-15-commonly-used-regex/


Don't escape the underscore. Might be causing some whackness.

What is an example of an alphanumeric username?, Hello -- I'd like to expand the Regex below to allow not only alphanumeric characters, but also hyphen, underscore, space. Regex  In previous articles I explained jQuery regular expression to validate url without http(s), regular expression to validate phone number in jquery, regular expression to replace all special characters with spaces in c#, regex email validation in c# and many articles relating to validation, JQuery. Now I will explain regular expression to allow


Regex check for alphanumeric, hyphen, underscore, space, Alphanumeric, dash and underscore but no spaces regular expression check Javascript. var regexp = /^[a-zA-Z0-9-_]+$/;. var check  That leaves in the letter, numbers, and underscore, but I need to also allow dash and periods. I'm not sure what the correct regex to select the dash and periods as well would be. Best How To :


Alphanumeric, Dash and Underscore Javascript Validation using , regular expression for alphanumeric, hyphen and underscore with space the above regex is working in Regex online editor however not working in data annotation in c# Test String Substitution characters and numbers with underscore. IDs markdown fenced code block FuncDefRegex1 Railcar Number match css & js  I'm trying to use a Regular Expression Validator that allows only Alphanumeric characters and spaces. My expression "^[0-9a-zA-Z]+$" seems to be working only if there are no spaces. How do I modify the expression to allow Space? Thanks.


Regex for alpha number string in c# accepting underscore and white , regular expression for alphanumeric, hyphen and underscore with space might not work for all regex engines, but the above certainly works in Javascript (as seen in Will Alphanumeric contain _ and space?, Can I validate a string and only  Regular expressions are patterns used to match character combinations in strings. In JavaScript, regular expressions are also objects. These patterns are used with the exec() and test() methods of RegExp, and with the match(), matchAll(), replace(), search(), and split() methods of String. This chapter describes JavaScript regular expressions.