var ajax = new Array();

function get_model(sel) {
    var autoMerk = sel.options[sel.selectedIndex].value;
    document.getElementById('modellen').options.length = 0;    // Empty city select box
    if(autoMerk.length>0){
        var index = ajax.length;
        ajax[index] = new sack();

        ajax[index].requestFile = 'ajax_get_merken.php?wat=model&id='+autoMerk;    // Specifying which file to get
        ajax[index].onCompletion = function(){ createMerken(index) };    // Specify function that will be executed after file has been found
        ajax[index].runAJAX();        // Execute AJAX function
    }
}

function createMerken(index) {
    var obj = document.getElementById('modellen');
    eval(ajax[index].response);    // Executing the response from Ajax as Javascript code
}

function get_type(sel) {
    var autoModel = sel.options[sel.selectedIndex].value;
    document.getElementById('uitvoeringen').options.length = 0;    // Empty city select box
    if(autoModel.length>0){
        var index = ajax.length;
        ajax[index] = new sack();

        ajax[index].requestFile = 'ajax_get_merken.php?wat=type&id='+autoModel;    // Specifying which file to get
        ajax[index].onCompletion = function(){ createUitvoeringen(index) };    // Specify function that will be executed after file has been found
        ajax[index].runAJAX();        // Execute AJAX function
    }
}

function createUitvoeringen(index) {
    var obj = document.getElementById('uitvoeringen');
    eval(ajax[index].response);    // Executing the response from Ajax as Javascript code
}