.length); ++i){
								data_labels.push(data_list[i][data_columns.indexOf("name")]);
								data.push(data_list[i][column_index]);
							}

							eval("var " + selected_column + " = { label: selected_column, data: data, type: 'line', fill: false, borderColor: borderColors[selected_column], borderWidth: 1 };");
							mainChart.data.datasets.unshift(eval(selected_column));
							mainChart.update();
						}
					} else {
						// if there is no 'line' dataset and the value is no 'none', add the new one
	