jquery中ajax如何返回值到上层函数里？

function selectFamCount(memberId,mutationId){
var count='';
$.ajax({
type:"post",
url:base+"/two-check/validate-order-mutation/selectFamCount.action?t=" + new Date().getTime(),
data:{"memberId":memberId,"mutationDataId":mutationId},
async:false,
success:function(data){
count = data.statusCode;
},
});
return count;

}

async:false,//这里选择异步为false，那么这个程序执行到这里的时候会暂停