Date.now formate meaning code example

Example 1: javascript today date in epoch

const start = Date.now(); 
/*gives the number of milliseconds elapsed since January 1, 1970 00:00:00 UTC.*/

Example 2: Datetime to utc format

string foo = yourDateTime.ToUniversalTime()
                         .ToString("yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fff'Z'");