HTML 将剪贴板图像粘贴到文件输入

Question

Okay, here it goes. I have seen the great ways in which one can now paste images to WhatsApp web chats. Most examples use a canvas to capture the pasted clipboard image, how does one paste it to a File Input using only Ctrl + V anywhere on the page ?

Here is the code I have for the input which automatically submits as soon as someone selected a file:

      <form id="new_document_attachment" method="post">
            <div class="actions"><input type="submit" name="commit" value="Submit" /></div>
                <input type="file" id="document_attachment_doc" />
      </form>
      <script>
          document.getElementById("document_attachment_doc").onchange = function() {
          document.getElementById("new_document_attachment").submit();
        };
      </script>

Answer 1

It's pretty straightforward. Just catch paste event on window object and put all the files you got from it to the <input> tag.

 const form = document.getElementById("new_document_attachment"); const fileInput = document.getElementById("document_attachment_doc"); fileInput.addEventListener('change', () => { form.submit(); }); window.addEventListener('paste', e => { fileInput.files = e.clipboardData.files; });

 <form id="new_document_attachment" method="post"> <div class="actions"><input type="submit" name="commit" value="Submit" /></div> <input type="file" id="document_attachment_doc" /> </form>

Answer 2

Work well

<form action="abc.php" method="post" enctype="multipart/form-data">
  <div class="actions"><input type="submit" name="commit" value="Submit" /></div>
  <input type="file" name="aaa"/>
</form>
  
 <script type="text/javascript">
//e.originalEvent.clipboardData.files
const form = document.getElementById("new_document_attachment");
const fileInput = document.getElementById("document_attachment_doc");

fileInput.addEventListener('change', () => {
  form.submit();
});

window.addEventListener('paste', e => {
  fileInput.files = e.clipboardData.files;
}); 
 </script>

PHP Output: var_dump($_FILES);

array (size=1)
  'aaa' => 
    array (size=5)
      'name' => string 'image.png' (length=9)
      'type' => string 'image/png' (length=9)
      'tmp_name' => string 'C:\wamp64\tmp\phpF6AF.tmp' (length=25)
      'error' => int 0
      'size' => int 9380

Answer 3

我只是想添加上面的示例代码才能工作，实际上我必须将 enctype="multipart/form-data" 属性添加到表单元素。