Update field value in another form

Update field value in another form

Help with syntax please.

I have a form [tasks] that records tasks and links them to the Jobs form [jobs] using a job number.

I've created script in the Task form that counts the number of active tasks against a job number and assigns the value to a variable called active_task_count.

What I want to do is update a field in the Jobs form called active_tasks with the value of the variable active_task_count against the specific job_number.

Martyn