var quantity_compared_items;

function createRequestObject() {
    var ro;
    var browser = navigator.appName;
    if(browser == "Microsoft Internet Explorer") {
	ro = new ActiveXObject("Microsoft.XMLHTTP");
    } else {
        ro = new XMLHttpRequest();
    }
    return ro;
}

var http = createRequestObject();

function sendRequest(cbox) {

    if (cbox.checked) { 
        if (quantity_compared_items > 9) {
    
	    alert("Может быть выбрано не более 10 устройств");
	    v = "cmpr_box_" + cbox.value;
	    w = document.getElementById(v);
	    if (w) w.checked = false;
	    return;
	}
    
        http.open("get", "cmpradd" + cbox.value + ".html");
        http.onreadystatechange = handleResponse;
        http.send(null);

    } else {
        http.open("get", "cmprdel" + cbox.value + ".html");
        http.onreadystatechange = handleResponse;
        http.send(null);

	v = "cmpr_box_" + cbox.value;
	w = document.getElementById(v);
	if (w) w.checked = false;
    }

}

function handleResponse() {   
    if(http.readyState == 4){  
        response = http.responseText;
        document.getElementById("compare_selected").innerHTML = response;
	quantity_compared_items = response.substring(4, response.indexOf("-->"));
    }
}

function uncheckall(a) {

    b = a.split("-");
    for (i = 0; i < b.length; i++) {
	v = "cmpr_box_" + b[i];
	w = document.getElementById(v);
	if (w) w.checked = false;
    }
    
    http.open("get", "cmprdel" + a + ".html");
    http.onreadystatechange = handleResponse;
    http.send(null);
}