Timezone-independent countdown. Well, not a countdown, but you know, find out how long it is between now and the specified time.

countdown.js

// Get date object for the current time.
var now = new Date();

// Now let's get a timestamp for midnight UTC time. 
// Well, one millisecond before midnight so we don't have to deal with incrementing.
var midnight = Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate(), 23, 59, 59, 999);

// And the number of minutes until that time.
var diffInMinutes = Math.round((midnight - now.getTime()) / (1000 * 60));

window.console.log("UTC midnight is " + diffInMinutes + " minutes away.");