JS对输入判断变化屏蔽中文输入法输入时连续触发事件的方法

  <input type="text" onfocus="filter_time()" value="xxx" id="wd">
        <script>
            var str = ‘‘;
            var now = ‘‘
            function filter_time() {
                var time = setInterval(filter_staff_from_exist, 100);
                $(this).bind(‘blur‘, function () {
                    clearInterval(time);
                });
            };

            filter_staff_from_exist = function () {
                now = $.trim($(‘#wd‘).val());
                if (now != ‘‘ && now != str) {
                    console.log(now);
                    alert("2434");
                }
                str = now;
            }
        </script>

还请知道原理的大神不吝赐教