When a HTML page the page is closed, we need to alert saying
"There are some data changed which is not saved, do you want to close?"
Is there JQuery built in method to know whether the form data is changed.
or need to follow a complex way,
1. Introduce a local java script variable and capture all the form data in onload event.
2. While Close the window, Compare the local java script variables and form input values, if there is a change alert.