how to set day time in rust code example

Example 1: get day start time in swift

extension Date {

    var startOfDay : Date {
        let calendar = Calendar.current
        let unitFlags = Set<Calendar.Component>([.year, .month, .day])
        let components = calendar.dateComponents(unitFlags, from: self)
        return calendar.date(from: components)!
   }

    var endOfDay : Date {
        var components = DateComponents()
        components.day = 1
        let date = Calendar.current.date(byAdding: components, to: self.startOfDay)
        return (date?.addingTimeInterval(-1))!
    }
}
//Usage:

    let myDate = Date()
    let startOfDate = myDate.startOfDay
    let endOfDate = myDate.endOfDay

Example 2: how to get the computer date and time jquery

var dt = new Date();
var time = dt.getHours() + ":" + dt.getMinutes() + ":" + dt.getSeconds();
document.write(time);