getElementById('lineChart').getContext('2d'),
barChart = document.getElementById('barChart').getContext('2d'),
pieChart = document.getElementById('pieChart').getContext('2d'),
doughnutChart = document.getElementById('doughnutChart').getContext('2d'),
radarChart = document.getElementById('radarChart').getContext('2d'),
bubbleChart = document.getElementById('bubbleChart').getContext('2d'),
multipleLineChart = document.getElementById('multipleLineChart').getContext('2d'),
multipleBarChart = document.getElement