Your daughter may be testing you to see if you are going to set consistent limits for her.  I suggest you set limits on this behavior, including consequences, right away, and do not back down.  Make the consequences simple for you to back up, such as loss of a privilege.  Be consistent.  Tell her:

"You may not treat me this way."  (name what she is doing, hitting, spitting etc, whatever it is. For example, "You may not hit me.  If you continue this behavior, you will lose......(a privilege)"  Then as the parent, make sure you do what you say you will do.

If safety needs are met for your daughter, you can tell her that you will need to go into another room because you cannot allow her to be violent with you.  Then you can remove your  presence for a while to let her calm down.  Often this type of violent behavior is a bid for parental attention.  And it does get it!  Removing attention when the child is safe can help reduce the behavior. A tip for you is to make sure you give her some quality attention when her behavior is appropriate.
Eliminating attention for negative behavior and giving attention for positive behavior can be a powerful combination.

In addition it may be a good idea to talk to your child's teacher and see if she/he can shed some light on what might be going on.  Even though this is not happening at school, the teacher knows your daughter, and the two of you might be able to understand if there are any underlying  problems that need to be dealt with.

Children will often show you that there is a problem by demonstrating it with their behavior.  If these suggestions fail to give results after a reasonable period of time, consider talking to a professional, such as a social worker.

Bette J. Freedson, LICSW, LCSW, CGP
Clinical Social Worker
JustAsk Expert