Reference > Script triggers reference > OnObjectModify
Performs a script when the value associated with an object changes as a result of the following:
a user types into an object
a user clicks an object such as a checkbox and causes the value to change
edit operations such as cut, paste, and clear
script steps such as the Insert Text script step that change a field
When the script runs
After the event has been processed.
Modes in which the trigger can be used
Browse and Find modes.
Where the script trigger is activated 
FileMaker Pro 
FileMaker Server 
FileMaker Go 
Custom Web Publishing 
FileMaker WebDirect 
Runtime solution 
Originated in 
FileMaker Pro 10.0
This script trigger activates if used in a panel control when the panels are switched.
This script trigger will not activate a script when the following operations are performed:
those described in Actions that don’t activate script triggers
a window is refreshed to update data from an external data source
auto-enter fields are updated
The OnObjectModify script trigger can be set for summary and calculation fields, but it will not activate.
The value of the script parameter that OnObjectModify passes to your script is determined before this trigger is activated. If you set OnObjectModify to activate on a field object, your script is run after the field is modified. Therefore, if your script needs the value before the field was modified, use the script parameter to pass the field's unmodified value into the script. However, if your script needs the modified value, include a step in the script that gets the field's current (modified) value.
FileMaker WebDirect does not support using the OnObjectModify script trigger to monitor keystrokes in a field (such as when a web user enters text via a keyboard, an input method editor, or a predictive-text suggestion). Monitoring keystrokes with OnObjectModify may reduce performance or lead to unexpected results.
Related topics 
Setting up script triggers
Setting script triggers for layouts
Setting script triggers for objects