If your JSON date is in the format like Date(1396895400000)
then Convert your JSON date to string format as follow :
var dt = new Date(parseInt((/Date(1396895400000)/).substr(6))).toString();
Then dt will look like Tue Apr 08 2014 00:00:00 GMT+0530 (India Standard Time)
Now take substring from dt as follow:
dt.substr(8, 2) + "-" + (dt.substr(4, 3)) + "-" + dt.substr(11, 4)
Then your date will look like 08-Apr-2014