Time Log added to current CRM (PHP. MySQL)

Add a simple start/stop timestamp to current PHP site (CRM), Not to complex. Client_ID User_ID (Display Username) Start Timestamp (Via Button) Stop Time Stamp (Via Button) Total Time in 1/10 hour Notes For Billable Time Display: Table Array with complete log for client Date Total Hours User Notes Admin Mode: Edit Start/Stop Timestamp with recalculate on submit Delete Record To be displayed as one line under client Info before notes Ajax timer in the section showing current time on project Report By Client or User w/date range Total billable time in the last 30 days/Since the 1st displayed in client file. User needs to be able to leave page then come back