通过启动时间和结束时间来计算时间持续时间。

I am using jQuery time picker to get start time and end time in 12hr format. I need to calculate time duration between start time and end time in HH:MM:SS format. I have the following code with me. But its returning duration like 1.1666. So what changes should I make in my code.I am using jQuery time picker to get start time