使用ajax中success后的返回值

function CheckForm(){        var pass;        var msg;        var url="${ctx}/crm/contact.action?method:checkForm";        var qq=document.getElementById("contact_QQ").value;        var mobile=document.getElementById("contact_mobile").value;        var email=document.getElementById("contact_email").value;        $.ajax({            url : url,            async:false,            type : "post",            dataType : "json",            data : {                    QQ:qq,                    mobile:mobile,                    email:email                },            success : function(data) {                pass=data.pass;                msg=data.msg;                if(pass){                    alert("保存成功！");                }else{                    alert(msg);                }            }      });        if(pass)            return true;        else            return false;    }        <button type="submit" class="btn btn-sm btn-primary savaBtn" name="method:save" onclick="return CheckForm()">保存</button>

重要的一步就是 async:false, 因为ajax默认是异步的，即 默认为async:true 。设为false后就可以把ajax中返回到前台的pass值在函数CheckForm中使用。
在Action中，

public void checkForm(){        String mobile=(String)getParameter("mobile", String.class);        String email=(String)getParameter("email", String.class);        String QQ=(String)getParameter("QQ", String.class);        boolean pass=true;        List mobileList = contactManager.find("from Contact where mobile=?",mobile);        List emailList = contactManager.find("from Contact where email=?",email);        List qqList = contactManager.find("from Contact where QQ=?",QQ);        //mobile不为空且size不为0，即有重复        if((!(mobile ==null || mobile.equals("")))&& mobileList.size()!=0){            pass=false;            msg+="手机号:"+mobile+ "  重复   ";                  }        if((!(email ==null || email.equals(""))) && emailList.size()!=0){            pass=false;            msg+="email:"+email+"  重复   ";                  }        if((!(QQ ==null || QQ.equals(""))) && qqList.size()!=0){            pass=false;            msg+="qq号:"+QQ+"  重复  ";            }        JSONObject resultObject = new JSONObject();        resultObject.put("pass", pass);        if(!(msg ==null || msg.equals(""))){            resultObject.put("msg", msg.substring(4));        }else{            resultObject.put("msg", msg);        }        System.out.println("==========");        System.out.println("pass"+pass);        System.out.println(resultObject.toString());        responseWrite(resultObject.toString());    }