[leon2009sp]

а можно еще вопрос?

function get_file(url, callback)
{
    xmlhttp=new XMLHttpRequest();
    xmlhttp.open("GET", url, true);
    xmlhttp.onreadystatechange = function()
    {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
        {
            callback(xmlhttp.responseText);
        }
    }
    xmlhttp.send();
}

window.addEventListener('DOMContentLoaded', function()
          {
            const day = (new Date()).getDay();
            let html = '<p>INFORMATION</p>';
            if (day == 1) html = '1.dat';
			if (day == 2) html = '2.dat';			
			if (day == 3) html = '3.dat'; 
			if (day == 4) html = '4.dat';
			if (day == 5) html = '5.dat';
			if (day == 6) html = '6.dat';
			if (day == 7) html = '7.dat';
            if (!day || day == 1) info.innerHTML = html;
			if (!day || day == 2) info.innerHTML = html;
			if (!day || day == 3) info.innerHTML = html; 
			if (!day || day == 4) info.innerHTML = html;
			if (!day || day == 5) info.innerHTML = html;
			if (!day || day == 6) info.innerHTML = html;
			if (!day || day == 7) info.innerHTML = html;
			
          }
		 
        );

get_file(html, function(response) 
{
    document.getElementById("output").innerHTML=response;
});

в общем вот не работает