Force browser to download image files on click

2019-01-01 13:42发布

站内文章 / JavaScript

30 0

何处买醉

女 | 书童

私信

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):

问题:

I need the browser to download the image files just as it does while clicking on an Excel sheet.

Is there a way to do this using client-side programming only?

<html xmlns=\"http://www.w3.org/1999/xhtml\">
    <head>
        <title></title>
        <script type=\"text/javascript\" src=\"Scripts/jquery-1.10.2.js\">
        $(document).ready(function () {
            $(\"*\").click(function () {
                $(\"p\").hide();
            });
        });
        </script>
    </head>

    <script type=\"text/javascript\">
        document.onclick = function (e) {
            e = e || window.event;
            var element = e.target || e.srcElement;
            if (element.innerHTML == \"Image\") {
                //someFunction(element.href);
                var name = element.nameProp;
                var address = element.href;
                saveImageAs1(element.nameProp, element.href);
                return false; // Prevent default action and stop event propagation
            }
            else
                return true;
        };

        function saveImageAs1(name, adress) {
            if (confirm(\'you wanna save this image?\')) {
                window.win = open(adress);
                //response.redirect(\"~/testpage.html\");
                setTimeout(\'win.document.execCommand(\"SaveAs\")\', 100);
                setTimeout(\'win.close()\', 500);
            }
        }
    </script>

    <body>
        <form id=\"form1\" runat=\"server\">
            <div>
                <p>
                    <a href=\"http://localhost:55298/SaveImage/demo/Sample2.xlsx\" target=\"_blank\">Excel</a><br />
                    <a href=\"http://localhost:55298/SaveImage/demo/abc.jpg\" id=\"abc\">Image</a>
                </p>
            </div>
        </form>
    </body>
</html>

How should it work in case of downloading an Excel sheet (what browsers do)?

回答1:

Using HTML5 you can add the attribute \'download\' to your links.

<a href=\"/path/to/image.png\" download>

Compliant browsers will then prompt to download the image with the same file name (in this example image.png).

If you specify a value for this attribute, then that will become the new filename:

<a href=\"/path/to/image.png\" download=\"AwesomeImage.png\">

UPDATE: As of spring 2018 this is no longer possible for cross-origin hrefs. So if you want to create <a href=\"https://i.imgur.com/IskAzqA.jpg\" download> on a domain other than imgur.com it will not work as intended. Chrome deprecations and removals announcement

回答2:

I managed to get this working in Chrome and Firefox too by appending a link to the to document.

var link = document.createElement(\'a\');
link.href = \'images.jpg\';
link.download = \'Download.jpg\';
document.body.appendChild(link);
link.click();
document.body.removeChild(link);

回答3:

Leeroy & Richard Parnaby-King:

UPDATE: As of spring 2018 this is no longer possible for cross-origin hrefs. So if you want to create on a domain other than imgur.com it will not work as intended. Chrome deprecations and removals announcement

function forceDownload(url, fileName){
    var xhr = new XMLHttpRequest();
    xhr.open(\"GET\", url, true);
    xhr.responseType = \"blob\";
    xhr.onload = function(){
        var urlCreator = window.URL || window.webkitURL;
        var imageUrl = urlCreator.createObjectURL(this.response);
        var tag = document.createElement(\'a\');
        tag.href = imageUrl;
        tag.download = fileName;
        document.body.appendChild(tag);
        tag.click();
        document.body.removeChild(tag);
    }
    xhr.send();
}

回答4:

var pom = document.createElement(\'a\');
pom.setAttribute(\'href\', \'data:application/octet-stream,\' + encodeURIComponent(text));
pom.setAttribute(\'download\', filename);
pom.style.display = \'none\';
document.body.appendChild(pom);
pom.click();
document.body.removeChild(pom);

回答5:

This is a general solution to your problem. But there is one very important part that the file extension should match your encoding. And of course, that content parameter of downlowadImage function should be base64 encoded string of your image.

const clearUrl = url => url.replace(/^data:image\\/\\w+;base64,/, \'\');

const downloadImage = (name, content, type) => {
  var link = document.createElement(\'a\');
  link.style = \'position: fixed; left -10000px;\';
  link.href = `data:application/octet-stream;base64,${encodeURIComponent(content)}`;
  link.download = /\\.\\w+/.test(name) ? name : `${name}.${type}`;

  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
}

[\'png\', \'jpg\', \'gif\'].forEach(type => {
  var download = document.querySelector(`#${type}`);
  download.addEventListener(\'click\', function() {
    var img = document.querySelector(\'#img\');

    downloadImage(\'myImage\', clearUrl(img.src), type);
  });
});

a gif image: <image id=\"img\" src=\"data:image/gif;base64,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\" />


<button id=\"png\">Download PNG</button>
<button id=\"jpg\">Download JPG</button>
<button id=\"gif\">Download GIF</button>

回答6:

Update Spring 2018

<a href=\"/path/to/image.jpg\" download=\"FileName.jpg\">

While this is still supported, as of February 2018 chrome disabled this feature for cross-origin downloading meaning this will only work if the file is located on the same domain name.

I figured out a workaround for downloading cross domain images after Chrome\'s new update which disabled cross domain downloading. You could modify this into a function to suit your needs. You might be able to get the image mime-type (jpeg,png,gif,etc) with some more research if you needed to. There may be a way to do something similar to this with videos as well. Hope this helps someone!

Leeroy & Richard Parnaby-King:

UPDATE: As of spring 2018 this is no longer possible for cross-origin hrefs. So if you want to create on a domain other than imgur.com it will not work as intended. Chrome deprecations and removals announcement

var image = new Image();
image.crossOrigin = \"anonymous\";
image.src = \"http://is3.mzstatic.com/image/thumb/Music62/v4/4b/f6/a2/4bf6a267-5a59-be4f-6947-d803849c6a7d/source/200x200bb.jpg\";
// get file name - you might need to modify this if your image url doesn\'t contain a file extension otherwise you can set the file name manually
var fileName = image.src.split(/(\\\\|\\/)/g).pop();
image.onload = function () {
    var canvas = document.createElement(\'canvas\');
    canvas.width = this.naturalWidth; // or \'width\' if you want a special/scaled size
    canvas.height = this.naturalHeight; // or \'height\' if you want a special/scaled size
    canvas.getContext(\'2d\').drawImage(this, 0, 0);
    var blob;
    // ... get as Data URI
    if (image.src.indexOf(\".jpg\") > -1) {
    blob = canvas.toDataURL(\"image/jpeg\");
    } else if (image.src.indexOf(\".png\") > -1) {
    blob = canvas.toDataURL(\"image/png\");
    } else if (image.src.indexOf(\".gif\") > -1) {
    blob = canvas.toDataURL(\"image/gif\");
    } else {
    blob = canvas.toDataURL(\"image/png\");
    }
    $(\"body\").html(\"<b>Click image to download.</b><br><a download=\'\" + fileName + \"\' href=\'\" + blob + \"\'><img src=\'\" + blob + \"\'/></a>\");
};

<script src=\"https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js\"></script>

回答7:

Try this:

<a class=\"button\" href=\"http://www.glamquotes.com/wp-content/uploads/2011/11/smile.jpg\" download=\"smile.jpg\">Download image</a>

回答8:

<html>
<head>
<script type=\"text/javascript\">
function prepHref(linkElement) {
    var myDiv = document.getElementById(\'Div_contain_image\');
    var myImage = myDiv.children[0];
    linkElement.href = myImage.src;
}
</script>
</head>
<body>
<div id=\"Div_contain_image\"><img src=\"YourImage.jpg\" alt=\'MyImage\'></div>
<a href=\"#\" onclick=\"prepHref(this)\" download>Click here to download image</a>
</body>
</html>

回答9:

I found that

<a href=\"link/to/My_Image_File.jpeg\" download>Download Image File</a>

did not work for me. I\'m not sure why.

I have found that you can include a ?download=true parameter at the end of your link to force a download. I think I noticed this technique being used by Google Drive.

In your link, include ?download=true at the end of your href.

You can also use this technique to set the filename at the same time.

In your link, include ?download=true&filename=My_Image_File.jpeg at the end of your href.

回答10:

You don\'t need to write js to do that, simply use:

<a href=\"path_to/image.jpg\" alt=\"something\">Download image</a>

And the browser itself will automatically download the image.

If for some reason it doesn\'t work add the download attribute. With this attribute you can set a name for the downloadable file:

<a href=\"path_to/image.jpg\" download=\"myImage\">Download image</a>

标签： javascript jquery html

何处买醉

女 | 书童

私信

收藏的人(0)

Ta的文章更多文章

0条评论

还没有人评论过~