TextBox1.Attributes.Add("onkeydown", "if(event.which || event.keyCode){if ((event.which == 13) || (event.keyCode == 13)) {document.getElementById('"+Button1.UniqueID+"').click();return false;}} else {return true}; ");

This line of code will cause that button Button1 will be “clicked” when visitors press Enter key and cursor is placed in TextBox1 textbox. On this way you can “connect” as many text boxes and buttons as you want.

If you remove document.getElementById(‘”+Button1.UniqueID+”‘).click(); the return key will not submit the form