<script type="text/javascript" 
            src="Jscript/jquery-1.4.2.js">
    </script>
    <script type="text/javascript" 
            src="Js-7-1/jquery.validate.js">
    </script>
    <script type="text/javascript" 
            src="Js-7-1/jquery.validate.messages_cn.js">
    </script>

<form id="frmV" method="get" action="#">
     <div class="divFrame">
         <div class="divTitle">
              請輸入下列資料
         </div>
         <div class="divContent">
              <div>
              標題：<br />
                  <input id="title" name="title"
                         type="text" class="txt" />
              <font color="red">*</font><br />
              <span></span>
              </div>
              <div>
         </div>
      </div>
         <div class="divBtn">
              <input id="sbtUser" type="submit" 
                     value="提交" class="btn" />
         </div>
     </div>
     </form>

<script type="text/javascript">
        $(function() {
            $("#frmV").validate(
              {
                  /*自定義驗證規則*/
                  rules: {
                      title: { required: true, minlength: 5,maxlength:18 }
                  },
                  /*錯誤提示位置*/
                  errorPlacement: function(error, element) {
                      error.appendTo(element.siblings("span"));
                  }
              }
            );
        })
    </script>

; (function($) {
    $.fn.extend({
          "focusColor":function (color) {
              var def_col = "#ccc";
              var list_bg = "#fff";
              color = (color == undefined )? def_col : color;
              $(this).find("li").each(function() {
                  $(this).mouseover(function() {
                      $(this).css("background-color", color);
                  }).mouseout(function() {
                      $(this).css("background-color", list_bg);
                  });
              });
              return $(this);
          }
    });
})(jQuery);

<script type="text/javascript">
        $(function() {
            $("#u1").focusColor("green");//調用自定義的插件
        })
    </script>

;$(function () {
    $.extend({
        "addNum": function (a, b) {
            a = a || 0;
            b = b || 0;
            return parseInt(a) + parseInt(b);
        }
    });
})(jQuery);

<script type="text/javascript">
        $(function() {
            $("#Button1").click(function() {
                $("#Text3").val(
                $.addNum($("#Text1").val(),
                         $("#Text2").val()));
            }); 
        })
    </script>