[Solved]-Scatter chart using HTML and Java Script (makeing y axis starting from zero (upside down) )-Highcharts

Since the tutorial is using HighCharts it would be good idea to open there docs.

As for answer you need to change this:

var yAxis = {
      title: {
         text: 'Weight (kg)'
      }
   };

To this:

var yAxis = {
      title: {
         text: 'Weight (kg)'
      },
      min: 0 // Make sure you add this.
   };

Hope that helps!