This is probably the easiest bar chart to create. Just a <div> with its size and background color set. About the only down side is printing. These will only print if you are using a browser that prints background colors/images.
Here I use a CSS style to set the color and a few other parameters. One advantage of doing this is that you could set a style sheet for printing and change from background color to 'border: 1pt solid red.' Borders print even when not printing background colors.
<style> div.bar { background-color: red; height: 20px; position: relative; } </style> <div class='bar' style='width:123px;'></div>