'use strict';
    var now = new Date();
    let testlist = document.getElementById ( 'test-list' ),
            listli = document.querySelectorAll ( "#test-list li" ),
            keywords = '["HTML", "CSS", "JAVASCRIPT"]',
            litxt = Array.from ( listli,x => x.textContent);
    var r = litxt.filter ( function ( s ) {
        if ( keywords.indexOf ( s.toUpperCase () ) != -1 ) {
            return s;
        }
    } );
    var str = " ";
    r.forEach ( function ( e ) {
        str += "<li>" + e + "</li>";
    } );
    testlist.innerHTML = str;
    var old=new Date();
    var time=old.getTime()-now.getTime();
    console.log(time);