This field will not accept special characters: (like !@#$%^&* etc)

This field will not accept double or single quotes:

This field will only accept numbers:

Key Check

View the source code. There are 3 different demonstration fields for checking against "key entry" of disallowed input. The invalid key characters are assigned within the code. These tests are performed at the time the key is pressed as opposed to getting into the field and then filtering it there. This is an essential concept for forms filtering and can be used in all valid character input situations.