How to prevent retyping typed texts in a textbox during page load

[mrjonessr41]

I have a page that handles error when there's one textbox with no content. Now for example I have 3 textboxes then I only put text on the two textbox. When I submit the page an error handler like "*" will appear right beside the empty textbox before the submit procedure. But the contents of the two textboxes were gone so I need to retyped what I've type before. How to prevent this?