Do something when a property changed?

[phaikawl]

I want to do something when a specific property of a QML object changed.
For example:
I have a QML TextEdit. I want to deselect() when its focus property changes from true to false.
How could I do it?

[lgeyer]

"QML Signal and Handler Event System":http://qt-project.org/doc/qt-4.8/qmlevents.html
[quote]Further, each QML properties have a <property_name>Changed signal and its corresponding on<property_name>Changed signal handler. As a result, property changes may notify other components for any changes.[/quote]