jquery ajax給外部變數賦值 async: false

開發過程中用到檢查是否存在手機號問題。

//驗證手機號是否註冊
            var bl = false;
            $.ajax({
                type: "post",
                async: false,//改為同步即可對外部變數賦值
                url: "ajax.ashx?isreg=1&tel=" + $("#tbtel").val(),
                success: function (data) {
                   
                      if (data == "1") {
                            bl = true;
                          layer.alert('該手機號已經註冊！', { skin: 'layui-layer-molv', icon: 6 });
                          
                    }
                }
            })
            if (bl == true)
                return;