I have a form field in which I want to allow 1 to 50 letters, numbers, and spaces in it. Just not start with a space and ends with a space. (Or, alternatively, if it starts with a space, it's not counted toward 50.)
I have something like:
^[^s][a-zA-Z0-9_ ]{1,50}[^s]$
But something like "AB" now doesn't pass, because nothing match the {1,50}.
EDIT:
The regex is for the HTML input element pattern field.
Or with minimal use of regex:
function myFunction() {
var input = document.getElementById('myInput').value.trim();
if (input.length < 1 || input.length > 50) {
document.body.innerHTML += "wrong lenth";
return false;
}
var re = /^[\w ]+$/;
if (re.exec(input) !== null) {
document.body.innerHTML += input + " is valid";
return true;
} else {
document.body.innerHTML += input + " is not valid";
return false;
}
}<input id="myInput">
<button onclick="myFunction()">Test</button>
My comment as an answer ;)
^\s*[a-zA-Z0-9_ ]{1,50}\s*$
This regex will allow entry of white space in the beginning and at the end without requiring it as your attempt (kind of) did.
Regards
Edit:
Combine Tims answer with this and you avoid space only:
^\s*\b[\w ]{1,50}$\s*
This forces the string to have a word boundary - i.e. must contain a word character.
s- guess you want anything but\s(whitespace). And that you can do with\S(capital S) -^\S[a-zA-Z0-9_ ]{1,50}\S$.^\s*[a-zA-Z0-9_ ]{1,50}\s*$which allows white space in the beginning and at the end, without them being included in the 50. (The logic of) Your regex requires white space in the beginning and the end.^[^\s][a-zA-Z0-9_ ]{1,50}\b$or^\b[\w ]{1,50}\b$regex101.com/r/lE5hS9/1