var date = {

　　isDuringDate: function (beginDateStr, endDateStr) {

　　var curDate = new Date(),

　　beginDate = new Date(beginDateStr),

　　endDate = new Date(endDateStr);

　　if (curDate >= beginDate && curDate <= endDate) {

　　　　return true;

　　}

　　　　return false;

　　}

}

var flag = date.isDuringDate('2020/04/04 00:00:00', '2020/04/04 23:59:59');

if (flag != false) {

　　var json={"filter":"grayscale(100%)","-webkit-filter":"grayscale(100%)","-moz-filter":"grayscale(100%)","-ms-filter":"grayscale(100%)","-o-filter":"grayscale(100%)","filter":"progid:DXImageTransform.Microsoft.BasicImage(grayscale=1)","-webkit-filter":"grayscale(1)"}

　　$("html").css(json);

}

// html{ filter: grayscale(100%); -webkit-filter: grayscale(100%); -moz-filter: grayscale(100%); -ms-filter: grayscale(100%); -o-filter: grayscale(100%); filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale"); filter:progid:DXImageTransform.Microsoft.BasicImage(grayscale=1); -webkit-filter: grayscale(1);}