ChartJSTooltip.js

tooltips: {
    // Disable the on-canvas tooltip
    enabled: false,

    custom: function(tooltipModel) {
        // Tooltip Element
        var tooltipEl = document.getElementById('chartjs-tooltip');

        // Create element on first render
        if (!tooltipEl) {
            tooltipEl = document.createElement('div');
            tooltipEl.id = 'chartjs-tooltip';
            tooltipEl.innerHTML = '<table></table>';
            document.body.appendChild(tooltipEl);
        }

        // Hide if no tooltip
        if (tooltipModel.opacity === 0) {
            tooltipEl.style.opacity = 0;
            return;
        }

        // Set caret Position
        tooltipEl.classList.remove('above', 'below', 'no-transform');
        if (tooltipModel.yAlign) {
            tooltipEl.classList.add(tooltipModel.yAlign);
        } else {
            tooltipEl.classList.add('no-transform');
        }

        function getBody(bodyItem) {
            return bodyItem.lines;
        }

        // Set Text
        if (tooltipModel.body) {
            var titleLines = tooltipModel.title || [];
            var bodyLines = tooltipModel.body.map(getBody);

            var innerHtml = '<thead>';

            titleLines.forEach(function(title) {
                innerHtml += '<tr><th>' + title + '</th></tr>';
            });
            innerHtml += '</thead><tbody>';

            bodyLines.forEach(function(body, i) {
                var colors = tooltipModel.labelColors[i];
                var style = 'background:' + colors.backgroundColor;
                style += '; border-color:' + colors.borderColor;
                style += '; border-width: 2px';
                var span = '<span style="' + style + '"></span>';
                innerHtml += '<tr><td>' + span + body + '</td></tr>';
            });
            innerHtml += '</tbody>';

            var tableRoot = tooltipEl.querySelector('table');
            tableRoot.innerHTML = innerHtml;
        }

        // `this` will be the overall tooltip
        var position = this._chart.canvas.getBoundingClientRect();

        // Display, position, and set styles for font
        tooltipEl.style.opacity = 1;
        tooltipEl.style.position = 'absolute';
        tooltipEl.style.left = position.left + window.pageXOffset + tooltipModel.caretX + 'px';
        tooltipEl.style.top = position.top + window.pageYOffset + tooltipModel.caretY + 'px';
        tooltipEl.style.fontFamily = tooltipModel._bodyFontFamily;
        tooltipEl.style.fontSize = tooltipModel.bodyFontSize + 'px';
        tooltipEl.style.fontStyle = tooltipModel._bodyFontStyle;
        tooltipEl.style.padding = tooltipModel.yPadding + 'px ' + tooltipModel.xPadding + 'px';
        tooltipEl.style.pointerEvents = 'none';
    }
}