html - restrict a character to type in a text box

Question

how we can restrict a character to type in a text box.

Answer 1

You can do this via javascript (so if javascript is off, you won't be able to restrict it)

<input type="text" onkeyup="this.value = this.value.replace(/[^a-z]/, '')" />

This will restrict it to only a-z characters. Checkout regular expressions to see what you can do