TheButton.js

;(function (window, $)
{ 
  'use strict';
  
  var TheButton = $('#thebutton');
  var DesiredTime = parseInt(window.prompt('Enter Your Desired Time: '), 10);
  
  console.log('The Button Will Be Pressed At: ' + DesiredTime + 's');
  
  var RunLoop = window.setInterval(function ()
  {
  	var currentTime = parseInt($('#thebutton-s-10s').text() + $('#thebutton-s-1s').text(), 10);
  	
  	if (currentTime <= (DesiredTime - 1))
  	{
  		TheButton.click();
  		window.clearInterval(RunLoop);
  		console.log('The Button Has Been Pressed...');
  	}
  }, 10);
})(window, jQuery);

This script is meant to be used on https://reddit.com/r/thebutton. When pasted into the console and run, it will prompt for your desired press time. Then, it will continue to run in the background until your time comes up, and it will press the button for you.

Note: If you refresh or leave the page, this will obviously stop running.