A functional resume is one organized around your skills, not around your employment history.
Functional resumes are difficult for human resource directors to follow.
They concentrate on describing specific functions but they lack dates and the name of the company involved. Too often they appear to be hiding something about the applicant because the dates and company names are missing. Stating objectives is outdated, and they are usually vague, at best. An employer assumes if you are applying for a position, you want that specific job. The employer is interested in what the applicant can do for his company, not what the applicant's goals are.