function doCheckEmail(value) {
  if (value.length > 0) {
    var req = new JsHttpRequest();
    req.onreadystatechange = function() {
        if (req.readyState == 4) {
            // Write result to page element (_RESULT becomes responseJS). 
            document.getElementById('checkmailmessage').innerHTML = req.responseJS.message;
        }
    }
    // Prepare request object (automatically choose GET or POST).
    req.open(null, '/users/checkmail_ajax.php', true);
    // Send data to backend.
    req.send( {  email: value  } );
  }
}


function doLoadRatingStars(good, rating) {
    var req = new JsHttpRequest();
    req.onreadystatechange = function() {
        if (req.readyState == 4) {
            // Write result to page element (_RESULT becomes responseJS). 
            document.getElementById('stars' + good).innerHTML = 
                req.responseJS.stars;
        }
    }
    // Prepare request object (automatically choose GET or POST).
    req.open(null, '/stars_ajax.php', true);
    // Send data to backend.
    req.send( {  good: good,
               rating: rating} );
}

function doLoadBuyAndBin(good, num) {
    document.getElementById('buymessage_' + num + '_' + good).innerHTML = "Секундочку, товар добавляется в корзину...";

    var req = new JsHttpRequest();
    req.onreadystatechange = function() {
        if (req.readyState == 4) {
            // Write result to page element (_RESULT becomes responseJS). 
            document.getElementById('binblock').innerHTML = req.responseJS.bin;
            document.getElementById('buymessage_' + num + '_' + good).innerHTML = req.responseJS.buymessage;

        }
    }
    // Prepare request object (automatically choose GET or POST).
    req.open(null, '/buyandbin_ajax2.php', true);
    // Send data to backend.
    req.send( {  good: good, 
		  num: num   } );
}

function doLoadUserLogin(frm) {
    document.getElementById('loginmessage').innerHTML = "Секундочку, происходит регистрация пользователя...";

    var req = new JsHttpRequest();
    req.onreadystatechange = function() {
        if (req.readyState == 4) {
            // Write result to page element (_RESULT becomes responseJS). 
            document.getElementById('userblock').innerHTML = req.responseJS.userblock;
            document.getElementById('loginmessage').innerHTML = req.responseJS.loginmessage;
        }
    }
    // Prepare request object (automatically choose GET or POST).
    req.open(null, '/login_ajax.php', true);
    // Send data to backend.
    req.send( { frm: frm } );
}

function doLoadUserLogout() {
//    document.getElementById('loginmessage').innerHTML = "Секундочку, производится выход пользователя...";

    var req = new JsHttpRequest();
    req.onreadystatechange = function() {
        if (req.readyState == 4) {
            // Write result to page element (_RESULT becomes responseJS). 
            document.getElementById('userblock').innerHTML = req.responseJS.userblock;
        }
    }
    // Prepare request object (automatically choose GET or POST).
    req.open(null, '/logout_ajax.php', true);
    // Send data to backend.
    req.send( { x: 1 } );
}