i have only one file named search.php . In which I have created one html form whose action is search.php i mean same page. Now when I press search button it shows the results but everytime browser jumps back to the top instead i want page to stay at same location after pressing search button. 
whenever you submit a form the browser counts the page reloaded as a new page, even if it’s the same. You could try javascript for what you’re looking for.
Couple of ways, 1 would be to use jquery, another would be to use link anchors.