This is a table that divides the whole document into left and right sides! Nesting "iframe" in a table is like a text box that can call specific attributes of an asp file: frameBorder="0 "means that iframe has no border. His name is "Carnock", and other practical styles 100% (height:100%; Width: 170 pixels) Width and height adapt to their own size, (visibility: inheritance; ) visibility inherits the parent class, (z-index: 2; ) layer sequence is 2.