in my project I want to save the leave of a temp where he took half day or full day from the calender.
You can choose times by using the plugin at http://trentrichardson.com/examples/timepicker/. This supports increments so by setting a 12 hour increment you can basically force to think in half day mode.
I implemented a version of this a little while ago. You can see a version of this at http://www.thewebdes.co.uk/dev/leave/. There's a link on there where you can get all the code I wrote for the project. I've commented it throughout.
Hope it helps.
Scott