使用后退按钮时的dateFormat datepicker

I have a datepicker on which I set a dateFormat of 'dd M yyyy'. This works fine on the initial load but when the user navigates to a different page and then clicks the back button to return the text box is left empty. If I remove the "dateFormat" the text box is repopulated when the back button is pressed.I have a datepicker on which I set a dateFormat