In order to remove non alphanumeric characters from a string we have used Replace and CHR commands.

Replace(string1,string2,string3) command will replace string2 by string3 in string.

For example:
            The code: <% =Replace("I love John","John","Peter") %>
             Output: I love Peter
 

CHR(integer) will return the ANSI character code specified by integer (must be 0 to 256). Values for integer to get alphanumeric characters are between 48-57(numbers), 65-90 (all caps letters)  and 97-122 (small caps letters).

For example:
            The code: <% =CHR(48) %>
            Output: 0
            The code: <% =CHR(65) %>
            Output: A
            The code: <% =CHR(97) %>
            Output: a

Additionally, ANSI character for CHR(32) is space.

Check all ANSI character for CHR(integer) here.

In the script bellow will remove all non-alphanumeric or spaces from variable Thetext. Ourput is in the right.