Javascript select onchange 未正确触发

<label><input type="checkbox" name="selection" value="wifi" checked onclick="filterLog(this)">wifi</label><br>
<select id="wifi" class="dropdownList" multiple size=3 onchange="filterLogSel()">

    function filterLogSel() {
        /* not fired by checkbox */
        if (!checkMark) {
            var breakCheck;
            /* remove all the content */
            var htmlSelectAdd = document.getElementById('logListBox');
            for(var i=0, n=htmlSelectAdd.length; i<n; i++) {
                htmlSelectAdd.options[i].remove();
                n--;
                i--;
            }
            /* add content according to the select value */
            selecttags = document.getElementsByClassName('dropdownList');
            for (key in jsonobj)
                for(var i=0, n=selecttags.length; i<n; i++) {
                    for(var j=0, m=selecttags[i].length; j<m; j++) {
                        if (selecttags[i].options[j].selected) {
                            var re=new RegExp(selecttags[i].options[j].value);
                            if ((re.exec(jsonobj[key]))!=null) {
                                selectBoxOption = document.createElement("option");
                                selectBoxOption.value = key;
                                selectBoxOption.text = jsonobj[key];
                                htmlSelectAdd.add(selectBoxOption,null);
                                breakCheck = true;
                                break;
                            }
                        }
                    }
                    if (breakCheck) {
                        breakCheck = false;
                        break;
                    }
                }
        }
    }

当我在 chrome 中调试它时，我发现当我单击选择标签中的选项时，它将触发复选框的 onclick 函数而不是选择的 onchange 函数。我希望触发选择的 onchange 函数。