//////////////////////////////////////////////////

var fields = new Array( document.getElementById('ur1'),
                        document.getElementById('ur2'),
                        document.getElementById('ur3'));

var nums = new Array();
nums[0] = 0;
nums[1] = 1;
nums[2] = 2;

//////////////////////////////////////////////////

function change_select(num) {

    if(num == 1) {
        nums[0] = -1;
        nums[1] = 1;
        nums[2] = 2;
        var ur1 = document.form_filter.ur1.options[document.form_filter.ur1.selectedIndex].value;
        makeRequest('get_options.php?ur1='+ur1);  
    } else if(num == 2) {
        nums[0] = 0;
        nums[1] = -1;
        nums[2] = 2;
        var ur2 = document.form_filter.ur2.options[document.form_filter.ur2.selectedIndex].value;
        makeRequest('get_options.php?ur2='+ur2);  
    } else if(num == 3) {
        nums[0] = 0;
        nums[1] = 1;
        nums[2] = -1;
        var ur3 = document.form_filter.ur3.options[document.form_filter.ur3.selectedIndex].value;
        makeRequest('get_options.php?ur3='+ur3);  
    }   
}

///////////////////////////////////////////////////

function clear_options(num) {
    var obj = fields[num];
    while (obj.options.length) {
        obj.remove(0);
    }
    obj.disabled = false;
}

////////////////////////////////////////////////// Ф-ция, принимающая данные с сервера

function receiveData(text) {
    var options = new Object();
    if(text) {
        eval(text);  // база данных - опции выпадающих списков  

        var where = (navigator.appName == "Microsoft Internet Explorer") ? -1 : null;
        var newElem;

        for (var j=0; j<3; j++) {
            var num = nums[j];

            if(num >= 0) {
                obj = fields[num];
                clear_options(num); 
                var db = options[num];

                for (var i=0; i<db.length; i++) {
                    newElem = document.createElement("option");
                    newElem.value = db[i].id;
                    newElem.text  = db[i].name;
                    if (db[i].sel == "1") {
                        newElem.selected = true;
                    }
                    if (db[i].is_zag == "1") {
                        newElem.style.background = "#EAEAEA";
                    }
                    obj.add(newElem, where);  
                }              
            }     
        }
    }
}
//////////////////////////////////////////////////

//makeRequest("get_options.php?ur1=2&ur2=33&ur3=&num=");

//////////////////////////////////////////////////