epoch-trigger.js

// set trigger time using https://www.epochconverter.com/ (know the trigger time in GMT)
triggerTime(1496300400000);

function run_script (){
	// put your logic here
}

// No need to alter any of this. 
function triggerTime(trigger) {
	var now = new Date().getTime();
	var timeout = ( trigger - now );
	setTimeout(function() { 
		run_script()
    }, timeout);
}