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Preview an image before it is uploaded

Posted by: admin November 2, 2017 Leave a comment

Questions:

I want to be able to preview a file (image) before it is uploaded. The preview action should be executed all in the browser without using Ajax to upload the image.

How can I do this?

Answers:

Please take a look at the sample code below:

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);
});
<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" />
</form>

Also, you can try this sample here.

Questions:
Answers:

There are a couple ways you can do this. The most efficient way would be to use URL.createObjectURL() on the File from your <input>. Pass this URL to img.src to tell the browser to load the provided image.

Here’s an example:

<input type="file" accept="image/*" onchange="loadFile(event)">
<img id="output"/>
<script>
  var loadFile = function(event) {
    var output = document.getElementById('output');
    output.src = URL.createObjectURL(event.target.files[0]);
  };
</script>

You can also use FileReader.readAsDataURL() to parse the file from your <input>. This will create a string in memory containing a base64 representation of the image.

<input type="file" accept="image/*" onchange="loadFile(event)">
<img id="output"/>
<script>
  var loadFile = function(event) {
    var reader = new FileReader();
    reader.onload = function(){
      var output = document.getElementById('output');
      output.src = reader.result;
    };
    reader.readAsDataURL(event.target.files[0]);
  };
</script>

Questions:
Answers:

One-liner solution:

Here is a code that uses blob object URLs, which is much more efficient than data URL when loading large images (imagine adding 4M markup to your HTML page !):

<img id="blah" alt="your image" width="100" height="100" />

<input type="file" 
    onchange="document.getElementById('blah').src = window.URL.createObjectURL(this.files[0])">

Generated URL will be like:

blob:http%3A//localhost/7514bc74-65d4-4cf0-a0df-3de016824345

Questions:
Answers:

The answer of LeassTaTT works well in “standard” browsers like FF and Chrome.
The solution for IE exists, but looks different. Here description of cross-browser solution:

In HTML we need two preview elements, img for standard browsers and div for IE

HTML:

<img id="preview" 
     src="" 
     alt="" 
     style="display:none; max-width: 160px; max-height: 120px; border: none;"/>

<div id="preview_ie"></div>

In CSS we specify the following IE specific thing:

CSS:

#preview_ie {
  FILTER: progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale)
}  

In HTML we include the standard and the IE-specific Javascripts:

<script type="text/javascript">
  {% include "pic_preview.js" %}
</script>  
<!--[if gte IE 7]> 
<script type="text/javascript">
  {% include "pic_preview_ie.js" %}
</script>

The pic_preview.js is the Javascript from the LeassTaTT’s answer. Replace the $('#blah') whith the $('#preview') and add the $('#preview').show()

Now the IE specific Javascript (pic_preview_ie.js):

function readURL (imgFile) {    
  var newPreview = document.getElementById('preview_ie');
  newPreview.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = imgFile.value;
  newPreview.style.width = '160px';
  newPreview.style.height = '120px';
}    

That’s is. Works in IE7, IE8, FF and Chrome. Please test in IE9 and report.
The idea of IE preview was found here:
http://forums.asp.net/t/1320559.aspx

http://msdn.microsoft.com/en-us/library/ms532969(v=vs.85).aspx

Questions:
Answers:

I have edited @Ivan’s answer to display “No Preview Available” image, if it is not an image:

function readURL(input) {
    var url = input.value;
    var ext = url.substring(url.lastIndexOf('.') + 1).toLowerCase();
    if (input.files && input.files[0]&& (ext == "gif" || ext == "png" || ext == "jpeg" || ext == "jpg")) {
        var reader = new FileReader();

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

        reader.readAsDataURL(input.files[0]);
    }else{
         $('.imagepreview').attr('src', '/assets/no_preview.png');
    }
}

Questions:
Answers:

Here’s a multiple files version, based on Ivan Baev’s answer.

The HTML

<input type="file" multiple id="gallery-photo-add">
<div class="gallery"></div>

JavaScript / jQuery

$(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]);
            }
        }

    };

    $('#gallery-photo-add').on('change', function() {
        imagesPreview(this, 'div.gallery');
    });
});

Requires jQuery 1.8 due to the usage of $.parseHTML, which should help with XSS mitigation.

This will work out of the box, and the only dependancy you need is jQuery.

Questions:
Answers:

Yes. It is possible.

Html

<input type="file" accept="image/*"  onchange="showMyImage(this)" />
 <br/>
<img id="thumbnil" style="width:20%; margin-top:10px;"  src="" alt="image"/>

JS

 function showMyImage(fileInput) {
        var files = fileInput.files;
        for (var i = 0; i < files.length; i++) {           
            var file = files[i];
            var imageType = /image.*/;     
            if (!file.type.match(imageType)) {
                continue;
            }           
            var img=document.getElementById("thumbnil");            
            img.file = file;    
            var reader = new FileReader();
            reader.onload = (function(aImg) { 
                return function(e) { 
                    aImg.src = e.target.result; 
                }; 
            })(img);
            reader.readAsDataURL(file);
        }    
    }

You can get Live Demo from here.

Questions:
Answers:

Example with multiple images using JavaScript (jQuery) and HTML5

JavaScript (jQuery)

function readURL(input) {
     for(var i =0; i< input.files.length; i++){
         if (input.files[i]) {
            var reader = new FileReader();

            reader.onload = function (e) {
               var img = $('<img id="dynamic">');
               img.attr('src', e.target.result);
               img.appendTo('#form1');  
            }
            reader.readAsDataURL(input.files[i]);
           }
        }
    }

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

Markup (HTML)

<form id="form1" runat="server">
    <input type="file" id="imgUpload" multiple/>
</form>

Questions:
Answers:

Clean and simple
JSfiddle

<img id="image-preview"  style="height:100px; width:100px;"  src="" >

<input style="display:none" id="input-image-hidden" onchange="document.getElementById('image-preview').src = window.URL.createObjectURL(this.files[0])" type="file" accept="image/jpeg, image/png">

<button  onclick="HandleBrowseClick('input-image-hidden');" >UPLOAD IMAGE</button>


<script type="text/javascript">
function HandleBrowseClick(hidden_input_image)
{
    var fileinputElement = document.getElementById(hidden_input_image);
    fileinputElement.click();
}     
</script>

This will be useful when you want a custom designed image upload button.

Questions:
Answers:

How about creating a function that loads the file and fires a custom event. Then attach a listener to the input. This way we have more flexibility to use the file, not just for previewing images.

/**
 * @param {domElement} input - The input element
 * @param {string} typeData - The type of data to be return in the event object. 
 */
function loadFileFromInput(input,typeData) {
    var reader,
        fileLoadedEvent,
        files = input.files;

    if (files && files[0]) {
        reader = new FileReader();

        reader.onload = function (e) {
            fileLoadedEvent = new CustomEvent('fileLoaded',{
                detail:{
                    data:reader.result,
                    file:files[0]  
                },
                bubbles:true,
                cancelable:true
            });
            input.dispatchEvent(fileLoadedEvent);
        }
        switch(typeData) {
            case 'arraybuffer':
                reader.readAsArrayBuffer(files[0]);
                break;
            case 'dataurl':
                reader.readAsDataURL(files[0]);
                break;
            case 'binarystring':
                reader.readAsBinaryString(files[0]);
                break;
            case 'text':
                reader.readAsText(files[0]);
                break;
        }
    }
}
function fileHandler (e) {
    var data = e.detail.data,
        fileInfo = e.detail.file;

    img.src = data;
}
var input = document.getElementById('inputId'),
    img = document.getElementById('imgId');

input.onchange = function (e) {
    loadFileFromInput(e.target,'dataurl');
};

input.addEventListener('fileLoaded',fileHandler)

Probably my code isn’t as good as some users but I think you will get the point of it. Here you can see an example

Questions:
Answers:

What about this solution?

Just add the data attribute “data-type=editable” to an image tag like this:

<img data-type="editable" id="companyLogo" src="http://www.coventrywebgraphicdesign.co.uk/wp-content/uploads/logo-here.jpg" height="300px" width="300px" />

And the script to your project off course…

function init() {
    $("img[data-type=editable]").each(function (i, e) {
        var _inputFile = $('<input/>')
            .attr('type', 'file')
            .attr('hidden', 'hidden')
            .attr('onchange', 'readImage()')
            .attr('data-image-placeholder', e.id);

        $(e.parentElement).append(_inputFile);

        $(e).on("click", _inputFile, triggerClick);
    });
}

function triggerClick(e) {
    e.data.click();
}

Element.prototype.readImage = function () {
    var _inputFile = this;
    if (_inputFile && _inputFile.files && _inputFile.files[0]) {
        var _fileReader = new FileReader();
        _fileReader.onload = function (e) {
            var _imagePlaceholder = _inputFile.attributes.getNamedItem("data-image-placeholder").value;
            var _img = $("#" + _imagePlaceholder);
            _img.attr("src", e.target.result);
        };
        _fileReader.readAsDataURL(_inputFile.files[0]);
    }
};

// 
// IIFE - Immediately Invoked Function Expression
// https://stackoverflow.com/questions/18307078/jquery-best-practises-in-case-of-document-ready
(

function (yourcode) {
    "use strict";
    // The global jQuery object is passed as a parameter
    yourcode(window.jQuery, window, document);
}(

function ($, window, document) {
    "use strict";
    // The $ is now locally scoped 
    $(function () {
        // The DOM is ready!
        init();
    });

    // The rest of your code goes here!
}));

See demo at JSFiddle

Questions:
Answers:

I have made a plugin which can generate the preview effect in IE 7+ thanks to the internet, but has few limitations. I put it into a github page so that its easier to get it

$(function () {
		$("input[name=file1]").previewimage({
			div: ".preview",
			imgwidth: 180,
			imgheight: 120
		});
		$("input[name=file2]").previewimage({
			div: ".preview2",
			imgwidth: 90,
			imgheight: 90
		});
	});
.preview > div {
  display: inline-block;
  text-align:center;
}

.preview2 > div {
  display: inline-block; 
  text-align:center;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="https://rawgit.com/andrewng330/PreviewImage/master/preview.image.min.js"></script>
	Preview
	<div class="preview"></div>
	Preview2
	<div class="preview2"></div>

	<form action="#" method="POST" enctype="multipart/form-data">
		<input type="file" name="file1">
		<input type="file" name="file2">
		<input type="submit">
	</form>

Questions:
Answers:

Following is the working code.

<input type='file' onchange="readURL(this);" /> 
<img id="ShowImage" src="#" />

Javascript:

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

            reader.onload = function (e) {
                $('#ShowImage')
                    .attr('src', e.target.result)
                    .width(150)
                    .height(200);
            };

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

Questions:
Answers:

If you are using angular then do take a look at this ng-file-upload directive

Its pretty cool.

Questions:
Answers:

It’s my code.Support IE[6-9]、chrome 17+、firefox、Opera 11+、Maxthon3

HTML

<input type="file"  id="netBarBig"  onchange="changeFile(this)"  />
<img  src="" id="imagePreview" style="width:120px;height:80px;" alt=""/>

javascript:

<script>
   
function previewImage(fileObj, imgPreviewId) {
    var allowExtention = ".jpg,.bmp,.gif,.png";  //allowed to upload file type
    document.getElementById("hfAllowPicSuffix").value;
    var extention = fileObj.value.substring(fileObj.value.lastIndexOf(".") + 1).toLowerCase();
    var browserVersion = window.navigator.userAgent.toUpperCase();
    if (allowExtention.indexOf(extention) > -1) {
        if (fileObj.files) {
            if (window.FileReader) {
                var reader = new FileReader();
                reader.onload = function (e) {
                    document.getElementById(imgPreviewId).setAttribute("src", e.target.result);
                };
                reader.readAsDataURL(fileObj.files[0]);
            } else if (browserVersion.indexOf("SAFARI") > -1) {
                alert("don't support  Safari6.0 below broswer");
            }
        } else if (browserVersion.indexOf("MSIE") > -1) {
            if (browserVersion.indexOf("MSIE 6") > -1) {//ie6
                document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
            } else {//ie[7-9]
                fileObj.select();
                fileObj.blur(); 
                var newPreview = document.getElementById(imgPreviewId);

                newPreview.style.border = "solid 1px #eeeeee";
                newPreview.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod='scale',src='" + document.selection.createRange().text + "')";
                newPreview.style.display = "block";

            }
        } else if (browserVersion.indexOf("FIREFOX") > -1) {//firefox
            var firefoxVersion = parseFloat(browserVersion.toLowerCase().match(/firefox\/([\d.]+)/)[1]);
            if (firefoxVersion < 7) {//firefox7 below
                document.getElementById(imgPreviewId).setAttribute("src", fileObj.files[0].getAsDataURL());
            } else {//firefox7.0+ 
                document.getElementById(imgPreviewId).setAttribute("src", window.URL.createObjectURL(fileObj.files[0]));
            }
        } else {
            document.getElementById(imgPreviewId).setAttribute("src", fileObj.value);
        }
    } else {
        alert("only support" + allowExtention + "suffix");
        fileObj.value = ""; //clear Selected file
        if (browserVersion.indexOf("MSIE") > -1) {
            fileObj.select();
            document.selection.clear();
        }

    }
}
function changeFile(elem) {
    //file object , preview img tag id
    previewImage(elem,'imagePreview')
}

</script>

Questions:
Answers:
function assignFilePreviews() {
      $( 'input[data-previewable=\"true\"]' ).change(function() {
          var prvCnt = $(this).attr('data-preview-container');
          if(prvCnt) {
            if (this.files && this.files[0]) {
              var reader = new FileReader();
              reader.onload = function (e) {
                var img = $('<img>');
                img.attr('src', e.target.result);
                img.error(function() {
                  $(prvCnt).html('');
                });
                $(prvCnt).html('');
                img.appendTo(prvCnt);
              }
              reader.readAsDataURL(this.files[0]);
          }
        }
      });
    }
$(document).ready(function() {
     assignFilePreviews(); 
});

HTML

<input type="file" data-previewable="true" data-preview-container=".prd-img-prv" />
<div class = "prd-img-prv"></div>

This also handles case when file with invalid type ( ex. pdf ) is choosen

Questions:
Answers:

try this simple code it will work for you (ref and thanks to :http://opoloo.github.io/jquery_upload_preview/)

<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="CSS/tableStyle.css">
<link rel="stylesheet" type="text/css" href="CSS/tableStyleResponsive.css">


<script type="text/javascript" src="http://code.jquery.com/jquery-2.0.3.min.js"></script>
<script type="text/javascript" src="http://opoloo.github.io/jquery_upload_preview/assets/js/jquery.uploadPreview.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
  $.uploadPreview({
    input_field: "#image-upload",   // Default: .image-upload
    preview_box: "#image-preview",  // Default: .image-preview
    label_field: "#image-label",    // Default: .image-label
    label_default: "Choose File",   // Default: Choose File
    label_selected: "Change File",  // Default: Change File
    no_label: false                 // Default: false
  });
});
</script>

<style type="text/css">
#image-preview {
  width: 150px;
  height: 150px;
  position: relative;
  overflow: hidden;
  background-color: #ffffff;
  color: #ecf0f1;
  input {
    line-height: 200px;
    font-size: 200px;
    position: absolute;
    opacity: 0;
    z-index: 10;
  }
  label {
    position: absolute;
    z-index: 5;
    opacity: 0.8;
    cursor: pointer;
    background-color: #bdc3c7;
    width: 200px;
    height: 50px;
    font-size: 20px;
    line-height: 50px;
    text-transform: uppercase;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    margin: auto;
    text-align: center;
  }
}
</style>

<script type="text/javascript">
$(document).ready(function() {
  $.uploadPreview({
    input_field: "#image-upload",
    preview_box: "#image-preview",
    label_field: "#image-label"
  });
});
</script>



</head>
<body>

<div id="image-preview">
  <label for="image-upload" id="image-label">Choose File</label>
  <input type="file" name="image" id="image-upload" />
</div>
</body>
</html>

Questions:
Answers:

for my app, with encryped GET url parameters, only this worked. I always got a TypeError: $(...) is null.
Taken from https://developer.mozilla.org/en-US/docs/Web/API/FileReader/readAsDataURL

function previewFile() {
  var preview = document.querySelector('img');
  var file    = document.querySelector('input[type=file]').files[0];
  var reader  = new FileReader();

  reader.addEventListener("load", function () {
    preview.src = reader.result;
  }, false);

  if (file) {
    reader.readAsDataURL(file);
  }
}
<input type="file" onchange="previewFile()"><br>
<img src="" height="200" alt="Image preview...">