Javascript datePicker Controller : Hard Coded string working, 变量不是

Question

我正在使用可以在此处找到的日期选择器:

http://www.frequency-decoder.com/2011/10/11/unobtrusive-accessible-datepicker-widgit-v6

只要我对对象的 ID 进行硬编码，我就可以正常工作。即

var newid = "date" + maxidOnce.toString();
        datePickerController.createDatePicker({                           
            formElements:{"date1":"%Y-%m-%d"},
            statusFormat:"%l, %d %F %Y", 
            noFadeEffect:true
        }); 

但是，如果我用变量替换 id，它就不再有效了。我看不出有什么区别。

var newid = "oncedate" + maxidOnce.toString();
        datePickerController.createDatePicker({                           
            formElements:{newid:"%Y-%m-%d"},
            statusFormat:"%l, %d %F %Y", 
            noFadeEffect:true
        }); 

Answer 1

I don't see how there is any difference.

区别在于 JavaScript 对象键在使用 object literals 时不被解释为变量 .使用 bracket notation相反。

var newid = "oncedate" + maxidOnce;
var formElts = {};
formElts[newid] = "%Y-%m-%d";
datePickerController.createDatePicker({                           
    formElements: formElts,
    statusFormat: "%l, %d %F %Y", 
    noFadeEffect: true
});

// or, to write it another way,
var newid = "oncedate" + maxidOnce;
var options = {                           
    formElements: {},
    statusFormat: "%l, %d %F %Y", 
    noFadeEffect: true
};
options.formElements[newid] = "%Y-%m-%d";
datePickerController.createDatePicker(options);