javascript - 使用上传按钮上传图片

Question

我有一个上传按钮，允许用户只上传一张图片，它会显示在一个 div 中。上传图片后，如果用户点击图片，我想在弹出窗口中显示图片。请帮助我如何实现这一目标。

Answer 1

试试这段代码

function readURL(input) {
  if (input.files && input.files[0]) {
    var reader = new FileReader();

    reader.onload = function(e) {
      $('#blah').attr('src', e.target.result);
    }

    reader.readAsDataURL(input.files[0]);
  }
}

$("#imgInp").change(function() {
  readURL(this);
});

var modal = document.getElementById('myModal');
$("#blah").click(function() {
  modal.style.display = "block";
  $('.img').html(this);
});

var span = document.getElementsByClassName("close")[0];
span.onclick = function() {
  modal.style.display = "none";
}

/* The Modal (background) */

.modal {
  display: none;
  /* Hidden by default */
  position: fixed;
  /* Stay in place */
  z-index: 1;
  /* Sit on top */
  left: 0;
  top: 0;
  width: 100%;
  /* Full width */
  height: 100%;
  /* Full height */
  overflow: auto;
  /* Enable scroll if needed */
  background-color: rgb(0, 0, 0);
  /* Fallback color */
  background-color: rgba(0, 0, 0, 0.4);
  /* Black w/ opacity */
}


/* Modal Content/Box */

.modal-content {
  background-color: #fefefe;
  margin: 15% auto;
  /* 15% from the top and centered */
  padding: 20px;
  border: 1px solid #888;
  width: 50%;
  /* Could be more or less, depending on screen size */
}


/* The Close Button */

.close {
  color: #aaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
}

.close:hover,
.close:focus {
  color: black;
  text-decoration: none;
  cursor: pointer;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="form1" runat="server">
  <input type='file' id="imgInp" />
  <img id="blah" src="#" alt="your image" height="100" width="100" />
</form>

<div id="myModal" class="modal">

  <!-- Modal content -->
  <div class="modal-content">
    <span class="close">&times;</span>
    <div class="img"></div>
  </div>

</div>