单击“后退”按钮时如何保留表单数据

I am developing a rails app. (I don't think this is a rails-specific problem) There's a reservation process which is consisted of 3 steps. When a user is on step 2 page, if the user clicks 'Previous' button, the form data in step 1 should be the same as before.I am developing a rails app. (I don't think thi