如何在按下键盘上的“输入”键时将焦点转到按钮上

i have a aspx page with two buttons,"close" and "submit" button.when i press the enter key in the keyboard the focus automatically goes to "close" button and closes the page.Instead i want the focus to be focused on the "submit" button on pressing the enter key in the keyboard.i have a aspx page with two buttons,"close" and