Why my buttons does not work?

Question

Hello I wrote this code in HTML using javascript and chart.js :

 var chart_labels = ['06:00', '09:00', '12:00', '15:00', '18:00', '21:00']; var temp_dataset = ['1', '8', '10', '10', '9', '7']; var rain_dataset = ['0', '0', '6', '32', '7', '2']; var ctx = document.getElementById("forecast").getContext('2d'); var config = { type: 'bar', data: { labels: chart_labels, datasets: [{ type: 'line', label: "Temperature (Celsius)", yAxisID: "y-axis-0", fill: false, data: temp_dataset, }, { type: 'bar', label: "Precipitation (%)", yAxisID: "y-axis-1", data: rain_dataset, }] }, options: { scales: { yAxes: [{ position: "left", "id": "y-axis-0", }, { position: "right", "id": "y-axis-1", }] } } }; var forecast_chart = new Chart(ctx, config); $("#0").click(function() { var data = forecast_chart.config.data; data.datasets[0].data = temp_dataset; data.datasets[1].data = rain_dataset; data.labels = chart_labels; forecast_chart.update(); }); $("#1").click(function() { var chart_labels = ['00:00', '03:00', '06:00', '09:00', '12:00', '15:00', '18:00', '21:00']; var temp_dataset = ['5', '3', '4', '8', '10', '11', '10', '9']; var rain_dataset = ['0', '0', '1', '4', '19', '19', '7', '2']; var data = forecast_chart.config.data; data.datasets[0].data = temp_dataset; data.datasets[1].data = rain_dataset; data.labels = chart_labels; forecast_chart.update(); }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.5.0/Chart.min.js"></script> <canvas id="forecast" width="300" height="150"></canvas> <button id="0" type="button">Dataset 1</button> <button id="1" type="button">Dataset 2</button> 

But the problem is when I click on the button it has no effects... where is the problem according to you ? According to me, I define correctly my functions so it should be ok but it is not the case.

How can I solve this ?

Thank you !

Answer 1

As you are using jquery selector to select the buttons your event handlers and the code for chart.js should be inside $(document).ready() .So it will work. Check the below code -

<script>
$(document).ready(function(){
 var chart_labels = ['06:00', '09:00', '12:00', '15:00', '18:00', '21:00'];
var temp_dataset = ['1', '8', '10', '10', '9', '7'];
var rain_dataset = ['0', '0', '6', '32', '7', '2'];
var ctx = document.getElementById("forecast").getContext('2d');
var config = {
    type: 'bar',
    data: {
        labels: chart_labels,
        datasets: [{
            type: 'line',
            label: "Temperature (Celsius)",
            yAxisID: "y-axis-0",
            fill: false,
            data: temp_dataset,
        }, {
            type: 'bar',
            label: "Precipitation (%)",
            yAxisID: "y-axis-1",
            data: rain_dataset,
        }]
    },
    options: {
        scales: {
            yAxes: [{
                position: "left",
                "id": "y-axis-0",
            }, {
                position: "right",
                "id": "y-axis-1",
            }]
        }
    }
};
var forecast_chart = new Chart(ctx, config);
$("#0").click(function() {
    var data = forecast_chart.config.data;
    data.datasets[0].data = temp_dataset;
    data.datasets[1].data = rain_dataset;
    data.labels = chart_labels;
    forecast_chart.update();
});
$("#1").click(function() {
    var chart_labels = ['00:00', '03:00', '06:00', '09:00', '12:00', '15:00', '18:00', '21:00'];
    var temp_dataset = ['5', '3', '4', '8', '10', '11', '10', '9'];
    var rain_dataset = ['0', '0', '1', '4', '19', '19', '7', '2'];
    var data = forecast_chart.config.data;
    data.datasets[0].data = temp_dataset;
    data.datasets[1].data = rain_dataset;
    data.labels = chart_labels;
    forecast_chart.update();
});
});

</script>

Here is a working demo : https://jsfiddle.net/7t6vfdwf/2/

you can see the buttons are working to change the dataset on click.

Answer 2

您的HTML ID应该以字母而不是数字开头

SyntaxError: '#1' is not a valid selector