Employers will have one more questions that they are prohibited from asking potential employees:

 

What is your previous salary history?

 
Many states are enacting laws that prohibits an employer from asking potential employees about their salary history
 

These laws are aimed at bridging the pay gap between male and female employees and also to not let an employee's past compensation to be an obstacle to higher future compensation in a new job.

 

Many employers used an employee's previous compensation to set their starting pay in the new job.  Hence, once the question of prior compensation becomes prohibitive employees will be able to command better compensation in their new position.

 

Some states have already passed laws that are in effect while others have laws that are making its way through the legislature.

 
AT the federal government level there are no laws in place that mandates this. 
However, there is a new law making its way through the congress that will make this practice mandatory for all businesses in the U.S.
 

See a listing by State at the DOL website.