In contrast to a line chart, which is usually used to display averages or momentary values, bar charts are used to visualize data that belongs to discrete groups. Examples include daily, monthly, and weekly sales (the groups are days, months, and weeks respectively), page visits per user, fuel consumption for each car, and so on.
The Flot chart library can also draw bar charts. In this example, we're going to visualize the number of daily sales for the past seven days. We're also going to show the sales from separate products separately, stacked on top of each other.
We'll need to download Flot from the official website at http://www.flotcharts.org/ and extract the contents to a separate folder named