<form id="demoForm">
            <p>
                <label for="user">username:</label>
                <input type="text" name="username" id="user"/>
            </p>
            <p>
                <label for="pass">password:</label>
                <input type="password" name="password" id="pass"/>
            </p>
            <p>
                <label for="age">         age:</label>
                <input type="text" name="age" id="age"/>
            </p>
            <p>
                <label for="post">postcode:</label>
                <input type="text" name="PostCode" id="post"/>
            </p>
            <input type="submit" value="提交" id="btn"/>
        </form>

<script type="text/javascript">$(function  () {//用来绑定所需操作的form表单$('#demoForm').validate({  
                    rules:{       //返回元素验证规则//绑定元素的name值                        username:{    
                            required:true,    //设置为必填选项rangelength:[3,6]//最小长度和最大长度                        },
                        password:{//绑定元素的name值 required:true,    //设置为必填选项rangelength:[6,12]//最小长度和最大长度                        },
                        age:{     //绑定元素的name值 
//                            min:18,          //最小值//                            max:999,         //最大值range:[18,999],  //最小值和最大值rangelength:[1,3],//最小长度和最大长度digits:true      //正整数                        },
                        PostCode:{  //绑定元素的name值 required:true,   //设置为必填选项PostCode:true    //自定义验证                        }
                    },//验证错误时的提示                    messages:{    
                        username:{     //绑定元素的name值 required:'此项必填',    //提示的错误信息rangelength:'用户名长度为3-6位'        //提示的错误信息                        },
                        password:{     //绑定元素的name值 required:'此项必填' ,          //提示的错误信息rangelength:'用户名长度为6-12位'       //提示的错误信息                        },
                        age:{     //绑定元素的name值 range:'年龄必须是18--999之间',//提示的错误信息rangelength:'1~3位数',       //提示的错误信息digits:'年龄必须是正整数'     //提示的错误信息                        },
                        PostCode:{ //绑定元素的name值 required:'此项必填'        //提示的错误信息                        }
                    },//当表单通过验证执行的操作                    submitHandler:function  () {
                        alert("校验全部通过")
                    },//当未通过验证的表单提交时执行的操作                    invalidHandler:function () {
                        alert("no");
                    }
                });                
                //自定义一个表单验证$.validator.addMethod('PostCode',function(value){var reg=/^[0-9]{6}$/;return reg.test(value); 
                },'必须是邮编格式的')
            })</script>