All of us know how many people nowadays work abroad. It is important to stay legally in the foreign country, that’s why you need a temporary visa for it.
Temporary worker visa is issued for persons who want to enter United States for 
employment lasting a fixed period of time that is not considered permanent or indefinite. According to The U.S. Department of Homeland Security(DHS) during 2012 there were 165 million non-immigrant admissions to the United States. 1,900,582 of these admissions were temporary worker visas.