หากต้องการล้างแผนภูมิออกจากแคนวาส ให้ลบองค์ประกอบ
var resetCanvas = function(){
$('#results-graph').remove();
$('#graph-container').append('<canvas id = "results-graph"><canvas>');
canvas = document.querySelector('#results-graph');
ct = canvas.getContext('2d');
ct.canvas.width = $('#graph').width(); // here we are resizing the new canvas element to parent width
ct.canvas.height = $('#graph').height(); // here we are resizing the new canvas element to parent height
var a = canvas.width/2;
var b = canvas.height/2;
ct.font = '12pt Calibri';
ct.textAlign = 'Align Left';
ct.fillText('left aligned text on the canvas', a, b);
}; 