The system is the California Courts Protective Order Registry, launched in June by the San Francisco-based state Administrative Office of the Courts.
Marin County was the first to implement the system on June 7, followed by Santa Cruz County on June 14 and Santa Clara County on Monday.
The system enables police officers, sheriff's deputies and judges responding to a victim's complaint to do a computer search at any time of day or night by the name of an alleged abuser or harasser.
AOC spokesman Philip Carrizosa said most of the orders in the system are those issued against abusers in domestic violence cases.
But the registry also contains restraining orders and protective orders filed in other types of cases, including elder abuse and workplace harassment situations.
When fully implemented statewide, the registry will show any orders issued against an individual in any California county and will show an exact image of each order, including the dates it is in effect and any notes handwritten by a judge.
"The registry will empower judges to make more informed decisions and avoid issuing conflicting orders," AOC staff member Christine Patton said.
"It will also improve public safety and the safety of law enforcement officers by providing access to more accurate, complete and up-to-date information about protective orders," she said.
Patton is the AOC's regional court services administrator for the Bay Area and northern coastal California.
Carrizosa said the registry is intended to address two related problems identified in the interim report of a state domestic violence task force in 2006.
First, he said, some judges don't have easy access to orders that might have been issued against an alleged abuser in another county.
Data from such orders is stored in another statewide system known as the California Law Enforcement Telecommunications System, or CLETS, but not all county Superior Court have access to that system.
Second, while police can use the CLETS system, it shows data but not the actual image of court orders and may not include items such as handwritten notes added to an order by a judge, Carrizosa said.
Seventeen more counties are expected to join the registry by December. Carrizosa said it is hoped that they will include Sonoma, Monterey and possibly Alameda counties.
The remaining 38 California counties will join the registry in the next few years, according to the AOC.
A $1 million grant from the California Emergency Management Agency is paying for project management expenses and scanning hardware for the first 20 courts, the AOC said.
A slightly different Internet registry is already in effect in Orange County.