This example shows how not to implement form
validation, using a blur event with programatic
focus to validate an input field. This forces a change in
the natural browsing behavior, and is both annoying and confusing for
users.
The correct way to implement form validation is described in: JS_F_A1, JS_F_A3 and JS_F_A4.
Type a value into the field below, then Tab or click away from it; if the value is not numeric the script will force the focus back into the field, until it is:
The JavaScript code for this example can be found in: JS_F_A5.js