How to Handle the Questions
The best way to handle a time gap of more than 2 years would be to be honest. If you took time off for personal reasons, for example, say so - but try not to give too many details. Usually, any information that you provide, will be accepted if the gap was a long time ago. Recent gaps in employment generally need more explanation.
You can try using different types of resume formats (depending on your situation) to cover the gap.
Functional Resume-Software professionals who have good experience in several technologies frequently use this resume style. Job seekers who have minimum experience also prefer this format. Job seekers who adopt the functional resume style systematize it through their specialized knowledge and capabilities. This resume style is purely functional, giving employment dates, company names, titles and positions.
This style also works well for homemakers who are returning to work after some time. The functional resume is not used as frequently as the chronological style, but if the candidate is well prepared, he can hide any gaps in employment and can be used as a marketing tool.
Chronological Resume-chronological format resume is also called the default format as this type of curriculum is organized in reverse chronological order starting with the titles of jobs; names of employers; dates of employment and results within a period of 10-15 years. This style is best for those who have great experience in a field and that don't have many employment gaps.
This resume style is well accepted, as it is usually short and concise, with details well specified. Job seekers who are looking for openings in the international job market also use this format.
How to Include the Explanation
If you prefer using a functional resume, you should include a short explanation for the gap in your cover letter. Including a legitimate explanation will always help - just make sure that you mention it in passing and don't get too detailed unless you are asked about it later.
If you have a big gap and don't mention it in your cover letter, then many recruiters may discard your resume thinking that you are not serious about your career.
If it is a minor employment gap, recruiters generally will realize, but if you had a more complex issue resulting in a larger gap, then it is better to specify it during the interview on your own.
The greatest interest of the employer, when he sees a gap in employment is whether this issue is an indication of their likely future absence. How do you deal with any gaps in your employment will usually determine whether you get an interview or not - so be prepared.