Pass image from one .jsp to another .jsp - javascript

I am learning JSP and I can't find an answer to the following question:
I want to upload the image file in one page, pass it to another and show it there like (based on this question):
first.jsp
<form method="post" onsubmit="save()" action="second.jsp" enctype="multipart/form-data">
<input type="file" name="openFile" onchange="reloadPreview()">
<canvas name="preview"></canvas>
<input type="submit" value="Save"/>
</form>
<script>
function reloadPreview(){
var preview = document.getElementsByName("preview")[0];
var file = document.getElementsByName("openFile")[0].files[0];
var reader = new FileReader();
var picture = new Image;
reader.onloadend = function () {
picture.src = reader.result;
preview.width = picture.width;
preview.height = picture.height;
var context = preview.getContext("2d");
context.drawImage(picture, 0, 0);
dataUrl = preview.toDataURL();
};
if (file) {
reader.readAsDataURL(file);
}
}
function save() {
window.location = "second.jsp?imgUrl="+dataUrl;
document.getElementById("form").submit();
}
var dataUrl;
</script>
1) What should I do to access canvas content from second.jsp?
2) Can I access openFile file without uploading it to canvas (for example if file is not an image)?

Source:
<%session.setAttribute("Down1","download.png");%>
<td>Image: </td>
<td><img src="download.png" width="516" height="516" alt="Down" name="Down1"/></td>
Destination:
<td><img src="download.png" width="516" height="516" alt="Down" name="Down1"/></td>

Related

Display image from a given url

I have an array with 3 cells.At the first cell i have a textarea where you can insert the url of an image.At the second cell i have a button which when you click the image display at the third cell where i have a div to display the image.The question is how can i display the image either from the internet either from local?
The code i wrote is:
function loadImage(){
var mydiv = document.getElementById("idofdivtodisplayimg");
var url = document.getElementById("idoftextareawhereyouputtheurl");
mydiv.innerHTML = url.value;
}
<html>
<body>
<input type="text" id="imagename" value="" />
<input type="button" id="btn" value="GO" />
<script type="text/javascript">
document.getElementById('btn').onclick = function() {
img = document.createElement('img');
img.src = document.getElementById('imagename').value;
document.body.appendChild(img);
}
</script>
</body>
</html>
You can see the sample code will add the images from an array to the document.
You could also append the images to any of the elements in your function by using url.appendChild
var arr = ['http://via.placeholder.com/350x150', 'http://via.placeholder.com/350x250','http://via.placeholder.com/350x350']; // hold image urls in an array.
arr.forEach(function(item){
// loop through array and add images to the document.
var img = new Image();
img.src = item;
document.body.appendChild(img);
});
In order to do both you would need to change your html and code.
For the case when the user has a url you can just create a new image and append it to your div setting the image's src to the url that was set in the input:
function loadImage(){
var mydiv = document.getElementById("idofdivtodisplayimg");
var url = document.getElementById("idoftextareawhereyouputtheurl");
var image = new Image;
mydiv.appendChild(image);
image.src = url.value;
}
Now to get it to display a local image you will need a file input or a drag and drop scheme as you cannot access local files without some type of user interaction.
So you would, for example, need to change your html to include a file input, and grab a reference to the selected file the user selects. Then use FileReader to read the file, and finally display it
HTML
<input type="file" id="imagefile">
JS
//input reference
var imageinput = document.getElementById("imagefile");
imageinput.addEventListener('change',function (){
var mydiv = document.getElementById("idofdivtodisplayimg");
var image = new Image;
mydiv.appendChild(image);
//FileReader instance
var reader = new FileReader;
reader.addEventListener('load',function(){
//reader.result will contain a dataURL that can be used
//like a regular image url
image.src = reader.result;
});
//read the file as a dataURL
reader.readAsDataURL( imageinput.files[0] );
});
This does both, it let's you upload an image (or at least load it to the browser) or give a URL to an image source. Click the button and the image is loaded and displayed!
This snippet uses the FileReader API to get the uploaded image and display it in an image element
function uploadOrNot() {
if (document.querySelector("input[type=file]").files[0]){
let input = document.querySelector("input[type=file]");
if (input.files && input.files[0]) {
var reader = new FileReader();
reader.onload = function(e) {
display(e.target.result);
}
reader.readAsDataURL(input.files[0]);
}
} else if (document.querySelector("input[type=text]").value){
display(document.querySelector("input[type=text]").value);
}
}
function display(res) {
let img = document.createElement("IMG");
img.src=res;
document.querySelector("#result").appendChild(img);
}
<div id="urlOrUpload">
<input type="text"/>
<br>
<input type="file" accetp="image/*"/>
</div>
<div id="buttonHolder">
<button type="button" onclick="uploadOrNot()">Display</button>
</div>
<div id="result"></div>
I partly solved it by replacing the div at the third cell with an img tag and at the function i wrote above, i chenged it to:
var image = document.getElementbyId("imageid");
var url = document.getElementbyId("urlid");
image.src = url.value;
But at the table i have,i also have a button where you can add a same row as above.How can i do this function for every url that is placed at every textbox?

How to send json format after make base64 encoded image

Here i am converting two images for base64 ,this one working fine after that i want make one json format, so i am trying like this but i no able to get answer. i am getting error like "message": "Uncaught ReferenceError: floor_image is not defined", how to solve this issue and send json format
$(document).ready(function(){
$('#submit').click(function(){
var filesSelected = document.getElementById("inputFileToLoad").files;
if (filesSelected.length > 0) {
var fileToLoad = filesSelected[0];
var fileReader = new FileReader();
fileReader.onload = function(fileLoadedEvent) {
var floor_image = fileLoadedEvent.target.result; // <--- data: base64
console.log("Converted Base64 version 1 " + floor_image); // i am getting answer here
}
fileReader.readAsDataURL(fileToLoad);
}
var filesSelected = document.getElementById("inputFileToLoad1").files;
if (filesSelected.length > 0) {
var fileToLoad = filesSelected[0];
var fileReader = new FileReader();
fileReader.onload = function(fileLoadedEvent) {
var property_image = fileLoadedEvent.target.result; // <--- data: base64
//console.log("Converted Base64 version 2 " + property_image); // i am getting answer here
}
fileReader.readAsDataURL(fileToLoad);
}
var json = {
"FloorImage" :floor_image,
"PropertyImage" : property_image
}
console.log(json);
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<form id="idname">
<input id="inputFileToLoad" type="file" /><br><br>
<input id="inputFileToLoad1" type="file" />
<br><br><br><br>
<input type="button" value="Submit" id="submit">
</form>
You do not have the floor_image in the global scope. Try to write var floor_image; outside of the method, then set floor_image to your result as you do, but remove the var keyword in the method. The same goes for property_image and json
Like this:
$(document).ready(function(){
var json={FloorImage:"not loaded yet",PropertyImage:"not loaded yet"};
var floor_image;
var property_image;
$('#submit').click(function(){
var filesSelected = document.getElementById("inputFileToLoad").files;
if (filesSelected.length > 0) {
var fileToLoad = filesSelected[0];
var fileReader = new FileReader();
fileReader.onload = function(fileLoadedEvent) {
floor_image = fileLoadedEvent.target.result;
json.FloorImage=floor_image;
}
fileReader.readAsDataURL(fileToLoad);
}
var filesSelected = document.getElementById("inputFileToLoad1").files;
if (filesSelected.length > 0) {
var fileToLoad = filesSelected[0];
var fileReader = new FileReader();
fileReader.onload = function(fileLoadedEvent) {
property_image = fileLoadedEvent.target.result;
json.PropertyImage=property_image;
}
fileReader.readAsDataURL(fileToLoad);
}
console.log(json); // you are logging the json before the images are loaded, because this code is executed before the code inside onLoad.
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form id="idname">
<input id="inputFileToLoad" type="file" /><br><br>
<input id="inputFileToLoad1" type="file" />
<br><br><br><br>
<input type="button" value="Submit" id="submit">
</form>
Scenario
Try to load the FloorImage first, you will see the text: "not loaded yet" in both properties of the json-object. Then try to load the PropertyImage, and you will se the base64 of the FloorImage inside your json-object, but the text "not loaded yet" on the PropertyImage. This is because the images are not finished loading when you print the json-object. However the images are there after the onload-method is done.
There are 2 problems:
floor_image and property_image are in local scope. You should
move them to click function's scope
onload is just a callback. It means that json object may
be created before files have loaded. You should only create it after
2 onload functions called (for example, use flag to determine
onload called or not, and only create json when both of them are
true)

image preview before upload file to server in jQuery? [duplicate]

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?
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>
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>
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
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
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
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" />
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');
}
}
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.
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.
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>
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>
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>
In React, if the file is in your props, you can use:
{props.value instanceof File && (
<img src={URL.createObjectURL(props.value)}/>
)}
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
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]);
}
}
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">
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
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.
<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>
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>
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>
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.
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=""/>
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>
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>
)
}
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);
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">
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...">
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

get width of uploaded image (before uploading file to server)

I have some code that i changed. It was prevusly to get file ext. I wannted it to get width of uploded image( before even clicking submit input ) and if it's too small giving alert. Problem is that i dont really know how i can connect this js code with html form.
<form id="add" method="POST" enctype="multipart/form-data" action="upload.php">
<input type="file" id= "filput" style="margin-bottom:30px; margin-top:20px;" name="file" size="40" />
</form>
$("#filput").on('change', function () {
var w = $(this).width();
if (w < 500) {
alert("too small");
} else {
alert("big");
}
});
The this referrs to the input not the image. You have too use the HTML5 file API.
You can use this example: How to get the image width from html 5 file API
Code example: copied from: Getting Image Dimensions using Javascript File API
$("#filput").on('change', function () {
var fr = new FileReader;
fr.onload = function() { // file is loaded
var img = new Image;
img.onload = function() {
alert(img.width); // image is loaded; sizes are available
};
img.src = fr.result; // is the data URL because called with readAsDataURL
};
fr.readAsDataURL(this.files[0]); // I'm using a <input type="file"> for demonstrating
});

File Validation in Javascript

We are working on a Email Encrypted Service. Here I have designed a html page (User Registration) where I have provided an area for uploading a file with extentions .crt, .cer and .der
This is HTML Content:
<section>
<label class="label">PubLic Key File</label>
<div>
<input type="file" id="fileInput">
</div>
<div id="fileDisplayArea"></div>
</section>
<button type="submit" class="button">Submit</button>
Javascript Code is:
window.onload = function() {
var fileInput = document.getElementById('fileInput');
var fileDisplayArea = document.getElementById('fileDisplayArea');
fileInput.addEventListener('change', function(e) {
var file = fileInput.files[0];
var imageType = /image.*/
if (file.type.match(imageType)) {
var reader = new FileReader();
reader.onload = function(e) {
fileDisplayArea.innerHTML = "";
var img = new Image();
img.src = reader.result;
fileDisplayArea.appendChild(img);
}
reader.readAsDataURL(file);
} else {
fileDisplayArea.innerHTML = "File not supported!";
}
});
}
I have copied this Javascript Code (beginner in javascript) . It Only Accepts image file. I want to change this code which only accepts .crt, .cer and .der Extentions.
Thank you :)
Your current regex will actually match any filename that contains the word "image" (any part of the filename that is "image" followed by zero or more characters)
If you want to match filenames that end in ".crt", ".cer" or ".der", you can use this regex:
var imageType = /\.crt|cer|der$/
You can test regular expressions using Rubular

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