Type marginheight='x' and replace the x with the number (in pixels) to set the margin between any page elements and the top and bottom of the web browser window.For example, to set the marginheight attribute to 20 pixels, type marginheight='20'..To set the individual top and bottom page margins, use the topmargin='x' and bottommargin='x' attributes in place of the marginheight='x' attribute, replacing x with the margin height in pixels.lick to select Notepad or WordPad.. Click OK.. Type marginwidth='x' and replace the x with a number (in pixels) to set the margin between any page elements (tables, images, etc.) and the left and right sides of the browser window.