Display the preview image before uploading it to the database

Question

I have a button called to add more images so that the user can add multiple images. Now, what I am doing, I have to display the preview image before uploading it to the database but it's not working as expected.

I referred to this link Preview images before upload

$(document).ready(function() {
  var max_fields = 5;
  var wrapper = $(".input_fields_wrap .row");
  var add_button = $(".add_field_button");
  var x = 1;

  $(add_button).click(function(e) {
    e.preventDefault();
    if (x < max_fields) {
      x++;
      $(wrapper).append('<div class="col-lg-4 mb-3"><div class="customfileWrap"><div class=" upload_file"><input type="file" name="slider[]"  class="fileupload" multiple><span class="excel_upload_icon"></span><p id="file-name"></p><span class="upload_text"> Click here to upload file </span> <div class="gallery"></div></div><a href="#" class="remove_field"> &#10006; </a></div></div>');

    }
  });

  $(wrapper).on("click", ".remove_field", function(e) {
    e.preventDefault();
    $(this).parent('div').parent('div').remove();
    x--;
  })

});

$(function() {
  // Multiple images preview in browser
  var imagesPreview = function(input, placeToInsertImagePreview) {

    if (input.files) {
      var filesAmount = input.files.length;

      for (i = 0; i < filesAmount; i++) {
        var reader = new FileReader();

        reader.onload = function(event) {
          $($.parseHTML('<img>')).attr('src', event.target.result).appendTo(placeToInsertImagePreview);
        }

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

  };

  $('.fileupload').on('change', function() {
    imagesPreview(this, 'div.gallery');
  });
});

.upload_file {
  border: 3px dashed #042954;
  position: relative;
  text-align: center;
  padding: 20px;
  border-radius: 3px;
  background: #f9f9f9;
  height: 120px;
}

.upload_file input {
  position: absolute;
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
  outline: none;
  opacity: 0;
  cursor: pointer;
}

.remove_field {
  position: absolute;
  top: -10px;
  right: -10px;
  color: #fff;
  background-color: red;
  width: 22px;
  height: 22px;
  text-align: center;
  border-radius: 20px;
}

.upload_file img {
  width: 100px;
}

.customfileWrap {
  position: relative;
}

.remove_field {
  position: absolute;
  top: -10px;
  right: -10px;
  color: #fff;
  background-color: red;
  width: 22px;
  height: 22px;
  text-align: center;
  border-radius: 20px;
}

<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/css/bootstrap.min.css" rel="stylesheet">

<section>
  <div class="container">
    <div class="input_fields_wrap">
      <button class="add_field_button mb-3">Add More Images</button>
      <div class="row">
        <div class="col-lg-4 mb-3">
          <div class="customfileWrap">
            <div class=" upload_file">
              <input type="file" name="slider[]" class="fileupload" multiple>
              <span class="excel_upload_icon"></span>
              <p id="file-name"></p>
              <span class="upload_text"> Click here to upload file </span>
              <!--  <img id="previewimg1" src="#" alt="" class="previewimg" /> -->
              <div class="gallery"></div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</section>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

Answer 1

The problem is that you haven't delegated the event handlers for dynamically generated file uploads:

$wrapper.on('change', '.fileupload', function() {
    imagesPreview(this, 'div.gallery');
});

const max_fields = 5;
const template = '<div class="col-lg-4 mb-3"><div class="customfileWrap"><div class=" upload_file"><input type="file" name="slider[]"  class="fileupload" multiple><span class="excel_upload_icon"></span><p id="file-name"></p><span class="upload_text"> Click here to upload file </span> <div class="gallery"></div></div><a href="#" class="remove_field"> &#10006; </a></div></div>';

// Multiple images preview in browser
const imagesPreview = function() {
  const input = this;
  const $placeToInsertImagePreview = $(this).parent().find('div.gallery');

  if (input.files) {
    var filesAmount = input.files.length;

    for (let i = 0; i < filesAmount; i++) {
      var reader = new FileReader();

      reader.onload = function(event) {
        $($.parseHTML('<img>')).attr('src', event.target.result).appendTo($placeToInsertImagePreview);
      }

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


$(function() {

  const $wrapper = $(".input_fields_wrap .row");
  const $add_button = $(".add_field_button");
  let fileUploadCount = 1;

  $add_button.click(e => {
    e.preventDefault();
    if (fileUploadCount < max_fields) {
      fileUploadCount++;
      $wrapper.append(template);
    }
  });

  $wrapper.on('click', '.remove_field', function(e) {
    e.preventDefault();
    $(this).closest('.customfileWrap').remove();
    fileUploadCount--;
  })

  $wrapper.on('change', '.fileupload', imagesPreview);

});

.upload_file {
  border: 3px dashed #042954;
  position: relative;
  text-align: center;
  padding: 20px;
  border-radius: 3px;
  background: #f9f9f9;
  height: 120px;
}

.upload_file input {
  position: absolute;
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
  outline: none;
  opacity: 0;
  cursor: pointer;
}

.remove_field {
  position: absolute;
  top: -10px;
  right: -10px;
  color: #fff;
  background-color: red;
  width: 22px;
  height: 22px;
  text-align: center;
  border-radius: 20px;
}

.upload_file img {
  width: 100px;
}

.customfileWrap {
  position: relative;
}

.remove_field {
  position: absolute;
  top: -10px;
  right: -10px;
  color: #fff;
  background-color: red;
  width: 22px;
  height: 22px;
  text-align: center;
  border-radius: 20px;
}

<link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/css/bootstrap.min.css" rel="stylesheet">

<section>
  <div class="container">
    <div class="input_fields_wrap">
      <button class="add_field_button mb-3">Add More Images</button>
      <div class="row">
        <div class="col-lg-4 mb-3">
          <div class="customfileWrap">
            <div class=" upload_file">
              <input type="file" name="slider[]" class="fileupload" multiple>
              <span class="excel_upload_icon"></span>
              <p id="file-name"></p>
              <span class="upload_text"> Click here to upload file </span>
              <!--  <img id="previewimg1" src="#" alt="" class="previewimg" /> -->
              <div class="gallery"></div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</section>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>