We help IT Professionals succeed at work.
Get Started

JavaScript/jQuery: Manipulate number in chart tooltip

hankknight asked
Last Modified: 2014-01-16
In this example, if you hover over a point on the chart, the value of x is displayed in a tooltip.  I want the value of x*2 to be displayed in the tooltip.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Flot Example</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
<script type="text/javascript" src="http:////cdnjs.cloudflare.com/ajax/libs/flot/0.8.1/jquery.flot.min.js"></script>
<script type="text/javascript" src="https://raw.github.com/krzysu/flot.tooltip/master/js/jquery.flot.tooltip.min.js"></script>
<div id="placeholder" style="width:600px;height:300px;"></div>
<script type="text/javascript">
var format = {
    grid: {
        show: true,
        aboveData: true,
        hoverable: true,
        autoHighlight: true,
        mouseActiveRadius: 20
    series: {
        lines: {
            show: true,
        points: {
            show: true
    xaxis: {
        show: true
    yaxis: {
        show: true
    tooltip: true,
    tooltipOpts: {
        content: "%x * 2 = ???",
        shifts: {
            x: -30,
            y: -50
    .ready(function () {
        var d1 = [];
        for(var i = 0; i < 61; i++)
            d1.push([i, Math.sin(i)]);
        $.plot($('#placeholder'), [{
            label: "Example",
            data: d1,
    }], format);

Open in new window

Watch Question
Most Valuable Expert 2013
This problem has been solved!
Unlock 1 Answer and 1 Comment.
See Answer
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE