Titanium 子串如何在钛上不起作用？

我正在使用datepicker选择日期

我的addEventlistener源代码在这里

$.picker.addEventListener('change',function(e){
    var date = e.value;
Ti.API.info(date); // shows '[INFO] :   2014-04-07 21:28:34 +0000' on console
    date.substring(0,10);

});

Ti.API.info（日期）显示正确的数据，但 日期子串（0,10）；显示如下所示的错误

[ERROR] :  Script Error {
[ERROR] :      backtrace = "#0 () at :0";
[ERROR] :      line = 143;
[ERROR] :      message = "'undefined' is not a function (evaluating 'date.substring(0, 10)')";
[ERROR] :      name = TypeError;
[ERROR] :      sourceId = 329234912;
[ERROR] :      sourceURL = "file:///Users/temp/Library/Application%20Support/iPhone%20Simulator/7.0.3/Applications/2E7B2C43-653A-4E38-BB04-F820AB2C3BC2/matomato.app/alloy/controllers/index.js";
[ERROR] :  }

---

对于您可以使用的日期：

var day = date.getDate();
var month = date.getMonth();
var year = date.getFullYear();
var newdate = year + "-" + month + "-" + day;

---

对于您可以使用的日期：

var day = date.getDate();
var month = date.getMonth();
var year = date.getFullYear();
var newdate = year + "-" + month + "-" + day;

---

对于您可以使用的日期：

var day = date.getDate();
var month = date.getMonth();
var year = date.getFullYear();
var newdate = year + "-" + month + "-" + day;

---

对于您可以使用的日期：

var day = date.getDate();
var month = date.getMonth();
var year = date.getFullYear();
var newdate = year + "-" + month + "-" + day;

---

将日期转换为字符串，然后您将能够使用子字符串

$.picker.addEventListener('change',function(e){
    var date = e.value;
        date= date.toString();   // check it
        date.substring(0,10); 
       Ti.API.info(date);       //'2014-04-07' 

});  

---

将日期转换为字符串，然后您将能够使用子字符串

$.picker.addEventListener('change',function(e){
    var date = e.value;
        date= date.toString();   // check it
        date.substring(0,10); 
       Ti.API.info(date);       //'2014-04-07' 

});  

---

将日期转换为字符串，然后您将能够使用子字符串

$.picker.addEventListener('change',function(e){
    var date = e.value;
        date= date.toString();   // check it
        date.substring(0,10); 
       Ti.API.info(date);       //'2014-04-07' 

});  

---

将日期转换为字符串，然后您将能够使用子字符串

$.picker.addEventListener('change',function(e){
    var date = e.value;
        date= date.toString();   // check it
        date.substring(0,10); 
       Ti.API.info(date);       //'2014-04-07' 

});