Implement AlphaNumeric validation for password in JavaScript

Here Mudassar Ahmed Khan has explained, how to implement AlphaNumeric validation i.e. allow users to enter only Alphabets and Numbers for password TextBox in JavaScript.t. The script works in such a way that the TextBox will accept only alphabets, numbers i.e. alphanumeric values with space character, thus unless a special character key has been specified to be excluded it won’t be accepted.