你可以先试着分开输入部分

you can try,first, to seperate the parts of the input

...
var input=$(this).val();
var month=input.substr(0,2)-1;
var day=input.substr(3,2);
var year=parseInt("20"+ input.substr(6,2));

然后启动一个新的Date对象：

and then initate a new Date object:

var date= new Date(year,month,day);

或将其写回现场，如下所示：

or write it back to the field, as you did:

$(this).val((date.getMonth()+1)+'/'+date.getDate()+'/'+date.getFullYear());