I'm trying to validate a name with regex, the regex stops the user from entering 2 spaces or dots in a row.
This is my code:
function test(input) {
var regex = /^[A-Za-z]+\.{0,1}\s{0,1}$/;
input.value = input.value.replace(regex, "");
}<input id="txt_NomCandidato" onkeyup="test(this);" type="text" class="form-control" name="txt_Nom">At the moment I want to enter a letter, I cant I don't know why, I hope you guys can help.
EDIT: Name only contains letters, not numbers.
With this solution it deletes only the second space or second dot and the first ones will still remain:
function test(input){
var regex=/\.(?=\.)|\s(?=\s)/;
input.value = input.value.replace(regex, "");
}<input id="txt_NomCandidato" onkeyup="test(this);" type="text" class="form-control" name="txt_Nom">The following regex should work for you: /[^a-zA-Z. ]|\.(?=\.)|\s(?=\s)/g
[^a-zA-Z. ]+ Limits all allowed characters to a-z, A-Z, dots, or spaces\.(?=\.) Limits it to only allow one dot in a row\s(?=\s) Limits it to only one space in a rowEach of these are separated by | (the or condition)
function test(input) {
var regex = /[^a-zA-Z. ]|\.(?=\.)|\s(?=\s)/g;
input.value = input.value.replace(regex, "");
}<input id="txt_NomCandidato" onkeyup="test(this);" type="text" class="form-control" name="txt_Nom">Your regex seems correct (it matches any string with no more than 1 space or 1 dot together), but your the logic in your function seems wrong.
What it's doing: anytime the value changes, take the value and replace anything that matches that regex with an empty string, so any time you write a character its replaced (because it matches the regex).
I would go with one of this options:
a) show a message if the value doesn't match the regex
b) change the regex to /.{2}| {2}/ and only replace the two dots or the two spaces, as Scath says in another answer
c) maybe just using the input pattern attribute with your original regex is enough: https://www.w3schools.com/TAGS/att_input_pattern.asp
Hope this helps!
To achieve expected result, use below option of slice
input.value.slice(-2) will return last two entered characters and if it is ".." or " "(double spaces) replace it with ''
function test(input){
if(input.value.slice(-2)=='..' || input.value.slice(-2)==' '){
input.value = input.value.replace(input.value.slice(-2), "");
}
}<input id="txt_NomCandidato" onkeyup="test(this);" type="text" class="form-control" name="txt_Nom">code sample - https://codepen.io/nagasai/pen/VXNOej
Your regex clears any characters starts with [A-Z] or [a-z] due to expression ^[A-Za-z]
This regex will not allow them to enter two periods or two spaces, when they enter the second of either it will clear.
function test(input){
var regex=/\.{2}| {2}/;
input.value = input.value.replace(regex, "").replace(/\d+|/g, '').replace(/\s+/g, ' ').replace(/[^\w]/, '');
}<input id="txt_NomCandidato" onkeyup="test(this);" type="text" class="form-control" name="txt_Nom">That is because you match [A-Za-z]+ which will match one or more characters and everything after that is optional.
Your regex would match.
[A-Za-z]+ Match one or more characters\.{0,1} Match optional dot (0 or 1 times)\s{0,1} match optional whitespace character (0 or 1 times)Which will match a and then you will do the replace.
To make something optional you could also use a question mark ?
To only allow characters, a single whitespace or a single dot you could replace all that does not match those criteria:
function test(input) {
var regex = /([. ])(?=\1)|[^a-zA-Z. ]/;
input.value = input.value.replace(regex, "");
}<form id="" name="">
<input id="txt_NomCandidato" onkeyup="test(this);" type="text" class="form-control" name="txt_Nom">
</form>To match a dot followed by a dot or a white space followed by a white space you could capture a dot or a white space in a group and it will match if it is followed by what is captured in the group using a positive lookahead.
{0,1}is the same as?