I have a javascript to allow just letters, numbers, space, _, - in one input:
var re = /^([a-zA-Z0-9 _-]+)$/;
if (!re.test(form.titulo.value)) {
alert("Error: Input contains invalid characters!");
form.titulo.focus();
return false;
}
the problem is, I want to allow ' too. So I can type something like: Ana's house, don't... I try to just add ' in the regex, but it didn't work:
/^([a-zA-Z0-9 _-']+)$/
This is because the hyphen in a character class indicates a range, unless it is at the end (where it clearly can't be a range) or is escaped. You can also remove capturing group as it is not required in your case.
Escape -
/^[a-zA-Z0-9 _\-']+$/
Move - at the beginning or end of the class
/^[a-zA-Z0-9 _'-]+$/
Demo
input {
color: green;
}
input:invalid {
color: red;
}<input type="text" pattern="[a-zA-Z0-9 _\-']+" />
Use
/^([a-zA-Z0-9 _'-]+)$/
When - is not the first or last character in the brackets, it means you're selecting a range of characters, like when you do a-z or 0-9. When you wrote _-' it meant all the characters between _ and '.
You can also escape the - to keep it from having special meaning.
/^([a-zA-Z0-9 _\-']+)$/
BTW, you can use \w as an abbreviation for a-zA-Z0-9_, so your regexp can be simplified to:
/^[\w \-']+$/
