change the format of date range input component

How to change the format of date range input component in cde.i am getting the format 'yyyy-mm-dd' but i need to change into 'dd-M-yy'.i have return a function under post execution section :

function()
{
var date1 = Dashboards.getParameterValue("parfromDate").toString();

var date2 = Dashboards.getParameterValue("partoDate").toString();
//alert(date1)
//alert(date2)

format = $.datepicker.formatDate("dd-M-yy",new Date(date1));

format2 = $.datepicker.formatDate("dd-M-yy",new Date(date2));


document.getElementById('render_SelectDate').value=format:format2;

}

the same function was working perfect in date input component but i m facing problem in date range component can any one suggest me where i m doing wrong ..