title: retain value after page refresh
body: <p>I am using a button control("validation button") in c#.
  I define some global variable in my project.
  when I clicked the button some form validation happens and an another button("save button") gets visible.
   the problem is when i click the validation button, the current page refreshes and the global variable doesn't contain the values. it shows null.
  how cal i maintain the value in global variable even after page refresh.</p>