CODEWITHSUNDEEP
javascriptjqueryfile-upload
Simbian
Simbian

Reputation: 21803

Preview an image before it is uploaded

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?

Upvotes: 2158

Views: 1853847

Answers (30)

w.Daya
w.Daya

Reputation: 530

Here is easy way to preview image

<input type="file" name="user_profile_image_path" id="user_profile_image_path" />
<img style="height: 150px; width: 150px;" src="" class="img-select profile preview_image">
<script>
$('#user_profile_image_path').on('change', function() {
    const file = this.files[0];
    if (!file) return;
    const reader = new FileReader();
    reader.onload = e => $('.preview_image').attr('src', e.target.result).show();
    reader.readAsDataURL(file);
});
</script>

Upvotes: 0

GMKHussain
GMKHussain

Reputation: 4661

To Preview MULTIPLE Files and Single file in single function with reusable approach using Plain JavaScript

function imagePreviewFunc(that, previewerId) {
    let files = that.files
        previewerId.innerHTML='' // reset image preview element

    for (let i = 0; i < files.length; i++) {
        let imager = document.createElement("img");
            imager.src = URL.createObjectURL(files[i]);
            previewerId.append(imager);
    }
}
<input accept="image/*" type='file' id="imageInput_1"
       onchange="imagePreviewFunc(this, imagePreview_1)" />
<div id="imagePreview_1">This Div for Single Image Preview</div>
  
<hr />
  
<input class="form-control" accept="image/*" type='file' id="imageInput_2" multiple="true"
       onchange="imagePreviewFunc(this, imagePreview_2)" />
<div id="imagePreview_2">This Div for Multiple Image Preview</div>

Upvotes: 3

Merrin K
Merrin K

Reputation: 1780

Try This

To PREVIEW the image before uploading it to the SERVER from the Browser without using Ajax or any complicated functions.

It needs an "onChange" event to load the image.

function preview() {
    frame.src=URL.createObjectURL(event.target.files[0]);
}
<form>
  <input type="file" onchange="preview()">
  <img id="frame" src="" width="100px" height="100px"/>
</form>

To preview multiple image click here

Upvotes: 76

Kamil Kiełczewski
Kamil Kiełczewski

Reputation: 92347

Short two-liner

This is size improvement of cmlevy answer - try

<input type=file oninput="pic.src=window.URL.createObjectURL(this.files[0])">
<img id="pic" />

Upvotes: 45

Ivan Baev
Ivan Baev

Reputation: 33901

imgInp.onchange = evt => {
  const [file] = imgInp.files
  if (file) {
    blah.src = URL.createObjectURL(file)
  }
}
<form runat="server">
  <input accept="image/*" type='file' id="imgInp" />
  <img id="blah" src="#" alt="your image" />
</form>

Upvotes: 3362

Irfan wani
Irfan wani

Reputation: 5055

Here is a much easy way to preview image before upload using pure javascript;

//profile_change is the id of the input field where we choose an image
document.getElementById("profile_change").addEventListener("change", function() {

//Here we select the first file among the selected files.
const file = this.files[0];

/*here i used a label for the input field which is an image and this image will 
  represent the photo selected and profile_label is the id of this label */
const profile_label = document.getElementById("profile_label");

//Here we check if a file is selected
if(file) {
    //Here we bring in the FileReader which reads the file info. 
    const reader = new FileReader();
    
    /*After reader loads we change the src attribute of the label to the url of the 
    new image selected*/
    reader.addEventListener("load", function() {
        dp_label.setAttribute("src", this.result);
    })

    /*Here we are reading the file as a url i.e, we try to get the location of the 
    file to set that as the src of the label which we did above*/
    reader.readAsDataURL(file);

}else {
    //Here we simply set the src as default, whatever you want if no file is selected.
    dp_label.setAttribute("src", "as_you_want")
}
});

And here is the HTML;

<label for="profile_change">
            <img title="Change Profile Photo" id="profile_label" 
             src="as_you_want" alt="DP" style="height: 150px; width: 150px; 
               border-radius: 50%;" >
</label>
<input style="display: none;" id="profile_change" name="DP" type="file" class="detail form-control">

Upvotes: 0

nkitku
nkitku

Reputation: 5708

https://stackoverflow.com/a/59985954/8784402

ES2017 Way

// convert file to a base64 url
const readURL = file => {
    return new Promise((res, rej) => {
        const reader = new FileReader();
        reader.onload = e => res(e.target.result);
        reader.onerror = e => rej(e);
        reader.readAsDataURL(file);
    });
};

// for demo
const fileInput = document.createElement('input');
fileInput.type = 'file';
const img = document.createElement('img');
img.attributeStyleMap.set('max-width', '320px');
document.body.appendChild(fileInput);
document.body.appendChild(img);

const preview = async event => {
    const file = event.target.files[0];
    const url = await readURL(file);
    img.src = url;
};

fileInput.addEventListener('change', preview);

Upvotes: 0

Merrin K
Merrin K

Reputation: 1780

TO PREVIEW MULTIPLE FILES using jquery

$(document).ready(function(){
    $('#image').change(function(){
        $("#frames").html('');
        for (var i = 0; i < $(this)[0].files.length; i++) {
            $("#frames").append('<img src="'+window.URL.createObjectURL(this.files[i])+'" width="100px" height="100px"/>');
        }
    });
});
<head>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
</head>
<body>
    <input type="file" id="image" name="image[]" multiple /><br/>
    <div id="frames"></div>
</body>

Upvotes: 12

Rachit Vohera
Rachit Vohera

Reputation: 745

<img id="blah" alt="your image" width="100" height="100" />
<input type="file" name="photo" id="fileinput" />
<script>
$('#fileinput').change(function() {
var url = window.URL.createObjectURL(this.files[0]);
 $('#blah').attr('src',url);
});
</script>

Upvotes: 2

Dmitri Dmitri
Dmitri Dmitri

Reputation: 585

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

Upvotes: 46

nkron
nkron

Reputation: 19791

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]);
    output.onload = function() {
      URL.revokeObjectURL(output.src) // free memory
    }
  };
</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>

Upvotes: 541

Melle
Melle

Reputation: 8357

In React, if the file is in your props, you can use:

{props.value instanceof File && (
    <img src={URL.createObjectURL(props.value)}/>
)}

Upvotes: 7

vishpatel73
vishpatel73

Reputation: 317

Preview multiple images before it is uploaded using jQuery/javascript?

This will preview multiple files as thumbnail images at a time

Html

<input id="ImageMedias" multiple="multiple" name="ImageMedias" type="file"
accept=".jfif,.jpg,.jpeg,.png,.gif" class="custom-file-input"  value="">                                    
<div id="divImageMediaPreview"></div>

Script

$("#ImageMedias").change(function () {
    if (typeof (FileReader) != "undefined") {
        var dvPreview = $("#divImageMediaPreview");
        dvPreview.html("");            
        $($(this)[0].files).each(function () {
            var file = $(this);                
                var reader = new FileReader();
                reader.onload = function (e) {
                    var img = $("<img />");
                    img.attr("style", "width: 150px; height:100px; padding: 10px");
                    img.attr("src", e.target.result);
                    dvPreview.append(img);
                }
                reader.readAsDataURL(file[0]);                
        });
    } else {
        alert("This browser does not support HTML5 FileReader.");
    }
});

Working Demo on Codepen

Working Demo on jsfiddle

I hope this will help.

Upvotes: 2

Wooster
Wooster

Reputation: 101

Here's a solution if you're using React:

import * as React from 'react'
import { useDropzone } from 'react-dropzone'

function imageDropper() {
  const [imageUrl, setImageUrl] = React.useState()
  const [imageFile, setImageFile] = React.useState()

  const onDrop = React.useCallback(
    acceptedFiles => {
      const file = acceptedFiles[0]
      setImageFile(file)

      // convert file to data: url
      const reader = new FileReader()
      reader.addEventListener('load', () => setImageUrl(String(reader.result)), false)
      reader.readAsDataURL(file)
    },
    [setImageFile, setImageUrl]
  )
  const { getRootProps, getInputProps, isDragActive } = useDropzone({ onDrop })

  return (
    <div>
      <div {...getRootProps()}>
        {imageFile ? imageFile.name : ''}
        {isDragActive ? <p>Drop files here...</p> : <p>Select image file...</p>}
        <input {...getInputProps()} />
      </div>
      {imageUrl && (
        <div>
          Your image: <img src={imageUrl} />
        </div>
      )}
    </div>
  )
}

Upvotes: 1

SHUBHASIS MAHATA
SHUBHASIS MAHATA

Reputation: 940

Default Iamge

                @Html.TextBoxFor(x => x.productModels.DefaultImage, new {@type = "file", @class = "form-control", onchange = "openFile(event)", @name = "DefaultImage", @id = "DefaultImage" })
                @Html.ValidationMessageFor(model => model.productModels.DefaultImage, "", new { @class = "text-danger" })
                    <img src="~/img/ApHandler.png"  style="height:125px; width:125px" id="DefaultImagePreview"/>
            </div>

 <script>
    var openFile = function (event) {
        var input = event.target;

        var reader = new FileReader();
        reader.onload = function () {
            var dataURL = reader.result;
            var output = document.getElementById('DefaultImagePreview');
            output.src = dataURL;
        };
        reader.readAsDataURL(input.files[0]);
    };
</script>

Upvotes: 1

Steve Jiang
Steve Jiang

Reputation: 743

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

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

Upvotes: 1

Jinu Joseph Daniel
Jinu Joseph Daniel

Reputation: 6291

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

Upvotes: -3

cnlevy
cnlevy

Reputation: 11038

One-liner solution:

The following code uses object URLs, which is much more efficient than data URL for viewing large images (A data URL is a huge string containing all of the file data, whereas an object URL, is just a short string referencing the file data in-memory):

<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

Upvotes: 304

Nisal Edu
Nisal Edu

Reputation: 7591

Try this

window.onload = function() {
  if (window.File && window.FileList && window.FileReader) {
    var filesInput = document.getElementById("uploadImage");
    filesInput.addEventListener("change", function(event) {
      var files = event.target.files;
      var output = document.getElementById("result");
      for (var i = 0; i < files.length; i++) {
        var file = files[i];
        if (!file.type.match('image'))
          continue;
        var picReader = new FileReader();
        picReader.addEventListener("load", function(event) {
          var picFile = event.target;
          var div = document.createElement("div");
          div.innerHTML = "<img class='thumbnail' src='" + picFile.result + "'" +
            "title='" + picFile.name + "'/>";
          output.insertBefore(div, null);
        });        
        picReader.readAsDataURL(file);
      }

    });
  }
}
<input type="file" id="uploadImage" name="termek_file" class="file_input" multiple/>
<div id="result" class="uploadPreview">

Upvotes: 3

Keyur
Keyur

Reputation: 1111

For Multiple image upload (Modification to the @IvanBaev's Solution)

function readURL(input) {
    if (input.files && input.files[0]) {
        var i;
        for (i = 0; i < input.files.length; ++i) {
          var reader = new FileReader();
          reader.onload = function (e) {
              $('#form1').append('<img src="'+e.target.result+'">');
          }
          reader.readAsDataURL(input.files[i]);
        }
    }
}

http://jsfiddle.net/LvsYc/12330/

Hope this helps someone.

Upvotes: 1

Siva Kannan
Siva Kannan

Reputation: 2461

Clean and simple JSfiddle

This will be useful when you want The event to triggered indirectly from a div or a button.

<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>

Upvotes: 11

Robert TheSim
Robert TheSim

Reputation: 433

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...">

Upvotes: -1

Ratan Paul
Ratan Paul

Reputation: 492

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>

Upvotes: 9

onin
onin

Reputation: 5760

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.

Upvotes: 21

Muhammad Awais
Muhammad Awais

Reputation: 4492

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]);
        }
    }

Upvotes: 6

Andrew
Andrew

Reputation: 2975

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>

Upvotes: 1

Rodolpho Brock
Rodolpho Brock

Reputation: 8145

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

Upvotes: 2

Md Rahman
Md Rahman

Reputation: 1820

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.

Upvotes: 18

Sachin Prasad
Sachin Prasad

Reputation: 5411

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');
    }
}

Upvotes: 28

ajorquera
ajorquera

Reputation: 1309

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

Upvotes: 6

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