When getting your taxes in order, the W-2 form can be one of the most important documents you will need, especially if you hope to claim a refund on any taxes paid out.
By law, it is a company's responsibility to ensure employees can access a W2 form where applicable. This needs to be provided before January 31.
However, not all employers make W2 forms available online
To provide a W 2 online, the employer has to make it available themselves (some employ a payroll company to do this)
if not available online, you can request the form via 'snail mail'.
I would also recommend you read what the IRS has to say about requesting a W2 form from 2013. The relevant information can be found here: www.irs.gov/pub/irs-pdf/iw2w3.pdf