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\-\_]$/;
var check = "checkme";
if (check.search(regexp) == -1)
{ alert('invalid'); }
else
{ alert('valid'); }
This question is related to
javascript
regex
However, the code below allows spaces.
No, it doesn't. However, it will only match on input with a length of 1. For inputs with a length greater than or equal to 1, you need a + following the character class:
var regexp = /^[a-zA-Z0-9-_]+$/;
var check = "checkme";
if (check.search(regexp) === -1)
{ alert('invalid'); }
else
{ alert('valid'); }
Note that neither the - (in this instance) nor the _ need escaping.
Try this
"[A-Za-z0-9_-]+"
Should allow underscores and hyphens
try this one, it is working fine for me.
"^([a-zA-Z])[a-zA-Z0-9-_]*$"
You shouldn't use String.match but RegExp.prototype.test (i.e. /abc/.test("abcd")) instead of String.search() if you're only interested in a boolean value. You also need to repeat your character class as explained in the answer by Andy E:
var regexp = /^[a-zA-Z0-9-_]+$/;
Don't escape the underscore. Might be causing some whackness.
Got stupid error. So post here, if anyone find it useful
[-\._] - means hyphen, dot and underscore[\.-_] - means all signs in range from dot to underscoreThis is the most concise syntax I could find for a regex expression to be used for this check:
const regex = /^[\w-]+$/;
Source: Stackoverflow.com