为什么正则表达式不允许使用字母？

Question

I am using this to restrict user from inputting numbers. I want him to only input alphabets like a,b,c,d,e etc

but it works oppositely.

  <input type="text" id="name" name="name" oninput="this.value = this.value.replace(/[A-Za-z]*/, '');" class="form-control" placeholder="Your name" required>

Answer 1

使用/[0-9]/, ''

  <input type="text" id="name" name="name" oninput="this.value = this.value.replace(/[0-9]/, '');" class="form-control" placeholder="Your name" required> 

Answer 2

Have you tried something like

this.value.replace(/[^A-Za-z]*/, '')

?

Answer 3

I would recommend using HTML5's pattern attribute instead, and mark invalid fields using the corresponding :invalid CSS modifier.

The difference is that the user may input numbers but won't be able to submit the form. This way he/she knows what's wrong and can fix his/her mistake.

Demo:

 input:invalid {border: 2px solid red;} 

 <form> <input type="text" id="name" name="name" placeholder="Your name" pattern="[^\\d]+" required> <input type="submit" /> </form> 

You can also add a custom validation message:

 document.addEventListener('DOMContentLoaded', function() { document.querySelectorAll('[data-invalid]').forEach(function (input) { input.addEventListener('invalid', function () { input.setCustomValidity(input.dataset.invalid); }); input.addEventListener('input', function () { input.setCustomValidity(''); }) }); }); 

 input:invalid {border: 2px solid red;} 

 <form> <input type="text" id="name" name="name" placeholder="Your name" pattern="[^\\d]+" data-invalid="Your name cannot contain numbers!" required> <input type="submit" /> </form>