'''H1B is one the non immigrant Visa type of the United States of America'''. H1B allows US employers to temporarily employ foreign workers in a specialist occupation. For H1B Visa, the application or the visa petition should explain the specialization field of the applicant with relevant practical and theoretical experiences.
When the H1B Visa India worker when employed for a company in the US loses his job, he could find another employer who could transfer his Visa or may choose to leave the United States within 7 days after losing the job.
The H1B visas are provided for 3 years validity with multiple entries initially and before expiry it could be extended for 3 more years at the maximum. A H1B worker could bring in his spouse and children as dependent applicants in the H4 Visa to the United States to stay with him during the period of his work in the United States.
A H1B Visa holder could work for more than one employer in the United States if the I-129 form is approved by each of the employers and abide by H1B work rules stated in the Department of Labor rules. Example: 40 hours a week of work etc.
H1B Visas could be transferred with the help of the new employer while you are in the United States on the H1B status. But such H1B transfers need a re-stamp of the Visa on your passport to be taken care in the US consulate before you re enter the United States after the H1 transfer.
For Example: You have transferred your H1B Visa from current employer to another employer, you would be getting the new I-94 forms from the United States government and you need to get your Visa stamped in your Indian embassy the next time you exit United States in order to get the eligibility to re enter the United States.
However there is a limitation on the number of H1B Visas per year by the US embassy, it is 65,000 issued per year.
Click [http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176...|here] to learn more about H1B Visas.