This guide is based on UK law. It was last updated in July 2008.
Some security experts say that AJAX forms are at greater risk of exploitation by virus writers because there are multiple communications between the form and the web server.
AJAX can also cause web accessibility problems, particularly for screen reader users. Since AJAX is increasingly popular in forms used in online shopping, and since the Disability Discrimination Act 1995 expects services like online shops to be accessible to and usable by disabled people, the problem presents a legal risk.
Like the security risk, the problem is not insurmountable – simply something to be aware of.