Use another page. Instead of using a textbox to pick the account number, use an input, that way you can control the "onkeypress" event. Then you can use a javascript function that counts teh characters that the user has entered. When the count reaches to 10, redirect the page to another one and send the account number as a parameter. Thus you can control the database connectivity and query on the page_load event in the new page and then show the info you'd like.
Greetings...