$(function(){
var starttime= -1;
var endtime = -1;
var ontime = new Date();
var onTime = new Date(new Date(ontime).toLocaleDateString()).getTime();
if(onTime >= starttime && onTime < endtime){
  $("html").css("filter","grayscale(1)");
  $("html").css("-webkit-filter","grayscale(100%)");
  $("html").css("-moz-filter","grayscale(100%)");
  $("html").css("-ms-filter","grayscale(100%)");
  $("html").css("-o-filter","grayscale(100%)");
  $("html").css("filter","progid:DXImageTransform.Microsoft.BasicImage(grayscale=1)");
}
})