why refresh page and there is one window open let you choose retry or cancel

Dear Sir,


When I refresh the page in IE. It showed one window and say: if you don't resend the information then you cannot refresh the page, choose retry to resend the information and choose cancel to cancel it.
How can i change my code to delete such window when I refresh my page? My page is www.jnbeacon.com/products.aspx

 
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