The top of the page includes a line of buttons to use some of ... Mouse Tracking — which uses the Processing.js library. Additional HTML and CSS has been added. Figure B The jsFiddle site ...

Include a CSS style parameter in your HR tag to modify the default color to black. Use an HTML or text editor to open the HTML page in which you want the line to appear. Type the following code ...

The likely problems are incorrect ordering in HTML files ... Add some CSS code to position the header. If you want the header aligned to one side, add the following line, changing "left" to ...