Employees need to access their email from wherever they happen to be – on the road, at customer sites, remote offices, and at home. WebMail clients allows receiving and sending email messages using POP3 and SMTP protocols through both local and remote mail servers. Providing secure filtering of unsafe content while viewing HTML-formatted email messages. WebMail clients can operate under different popular web platforms (PHP, ASP.NET, ruby on rails, java). So checkout this article for Ajax based php webmail clients.