var idFilterJS;
var isIE;
var eventsTable;
var req;

function applyFilter(){
    idFilterJS = getRadioValue();
    var url = "http://applyfilter?action=applyfilterXML&id=" + idFilterJS;
    req = initRequest();
    req.open("GET", url, true);
    req.onreadystatechange = applyFilterCallBack;
    req.send(null);
}

function getRadioValue() {
    var inputs = document.getElementsByName("filter");
    for (var i = 0; i < inputs.length; i++) {
        if (inputs[i].checked) {
            return inputs[i].value
        }
    }
}

function initRequest(){
    if (window.XMLHttpRequest) {
        if (navigator.userAgent.indexOf('MSIE') != -1){
            isIE = true;
        }
        return new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        isIE = true;
        return new ActiveXObject("Microsoft.XMLHTTP");
    }
}

<div id="filters-list">
    <form name="applyfilter" action="applyfilter">
        <fieldset>
            <legend>Filters</legend>
            <%
                for (int i = 0; i < userFilters.size(); i++) {
            %>
            <input type="radio" name="filter"
                   value="<%=userFilters.get(i).getId()%>"><%=userFilters.get(i).getName()%>
            <br/>
            <%
                }
            %>
            <button onclick="applyFilter();">Apply</button>

            <!--<button onclick="deleteFilter();">Delete filter</button>-->
        </fieldset>
    </form>
</div>