mozilla
Your Search Results

    Introduction to the Camera API

    Through the Camera API, it is possible to take pictures with your device's camera and upload them into the current web page. This is achieved through an input element with type="file" and an accept attribute to declare that it accepts images. The HTML looks like this:

    <input type="file" id="take-picture" accept="image/*">
    

    When users choose to activate this HTML element, they are presented with an option to choose a file, where the device's camera is one of the options. If they select the camera, it goes into picture taking mode. After the picture has been taken, the user is presented with a choice to accept or discard it. If accepted, it gets sent to the <input type="file"> element and its onchange event is triggered.

    Get a reference to the taken picture

    With the help of the File API you can then access the taken picture or chosen file:

    var takePicture = document.querySelector("#take-picture");
    takePicture.onchange = function (event) {
        // Get a reference to the taken picture or chosen file
        var files = event.target.files,
            file;
        if (files && files.length > 0) {
            file = files[0];
        }
    };
    

    Presenting the picture in the web page

    Once you have a reference to the taken picture (i.e., file), you can then use window.URL.createObjectURL() to create a URL referencing the picture and setting it as the src of an image:

    // Image reference
    var showPicture = document.querySelector("#show-picture");
    
    // Get window.URL object
    var URL = window.URL || window.webkitURL;
    
    // Create ObjectURL
    var imgURL = URL.createObjectURL(file);
    
    // Set img src to ObjectURL
    showPicture.src = imgURL;
    
    // For performance reasons, revoke used ObjectURLs
    URL.revokeObjectURL(imgURL);
    

    If createObjectURL() isn't supported, an alternative is to fallback to FileReader:

    // Fallback if createObjectURL is not supported
    var fileReader = new FileReader();
    fileReader.onload = function (event) {
        showPicture.src = event.target.result;
    };
    fileReader.readAsDataURL(file);
    

    Complete example

    If you want to see it in action, take a look at the complete working Camera API example.

    Here is the code used for that demo:

    HTML page

    <!DOCTYPE html>
    <html>
        <head>
            <meta charset="utf-8">
            <title>Camera API</title>
            <link rel="stylesheet" href="css/base.css" type="text/css" media="screen">
        </head>
    
        <body>
    
            <div class="container">
                <h1>Camera API</h1>
    
                <section class="main-content">
                    <p>A demo of the Camera API, currently implemented in Firefox and Google Chrome on Android. Choose to take a picture with your device's camera and a preview will be shown through createObjectURL or a FileReader object (choosing local files supported too).</p>
                    
                    <p>
                        <input type="file" id="take-picture" accept="image/*">
                    </p>
    
                    <h2>Preview:</h2>
                    <p>
                        <img src="about:blank" alt="" id="show-picture">
                    </p>
    
                    <p id="error"></p>
    
                </section>
    
                <p class="footer">All the code is available in the <a href="https://github.com/robnyman/robnyman.github.com/tree/master/camera-api">Camera API repository on GitHub</a>.</p>
            </div>
    
    
            <script src="js/base.js"></script>
    
    
        </body>
    </html>
    

    JavaScript file

    (function () {
        var takePicture = document.querySelector("#take-picture"),
            showPicture = document.querySelector("#show-picture");
    
        if (takePicture && showPicture) {
            // Set events
            takePicture.onchange = function (event) {
                // Get a reference to the taken picture or chosen file
                var files = event.target.files,
                    file;
                if (files && files.length > 0) {
                    file = files[0];
                    try {
                        // Get window.URL object
                        var URL = window.URL || window.webkitURL;
    
                        // Create ObjectURL
                        var imgURL = URL.createObjectURL(file);
    
                        // Set img src to ObjectURL
                        showPicture.src = imgURL;
    
                        // Revoke ObjectURL
                        URL.revokeObjectURL(imgURL);
                    }
                    catch (e) {
                        try {
                            // Fallback if createObjectURL is not supported
                            var fileReader = new FileReader();
                            fileReader.onload = function (event) {
                                showPicture.src = event.target.result;
                            };
                            fileReader.readAsDataURL(file);
                        }
                        catch (e) {
                            //
                            var error = document.querySelector("#error");
                            if (error) {
                                error.innerHTML = "Neither createObjectURL or FileReader are supported";
                            }
                        }
                    }
                }
            };
        }
    })();
    

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Camera API Not supported Not supported Not supported Not supported Not supported
    createObjectURL() 16 8.0 (8.0) 10+ Not supported Not supported
    FileReader 16 3.6 (1.9.2) 10+ 11.6+ Not supported
    Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Camera API 3.0 (Yes) 10.0 (10.0) Not supported Not supported Not supported
    createObjectURL() 4 (Yes) 10.0 (10.0) Not supported Not supported Not supported
    FileReader 3 (Yes) 10.0 (10.0) Not supported 11.1 Not supported

     

    Document Tags and Contributors

    Last updated by: Jeremie,