Displaying an Image and Checking Image Extension Before Uploading a File Using Javascript
My goal is to check the upload file first, this is an image, and if it is an image, I will show it. I receive codes from Verification Code and Image Code .
At first I was able to display the image. However, when I combined the image code with the validation code, I was unable to handle both the validation and the display.
Can anyone help me? Below are my codes. Thank you in advance!:)
<input type="file" name="dataFile" id="fileChooser" onchange="readURL(this);" />
<SCRIPT type="text/javascript">
var _validFileExtensions = [".jpg", ".jpeg", ".bmp", ".gif", ".png"];
function readURL(input) {
var arrInputs = document.getElementById("fileChooser").value;
for (var i = 0; i < arrInputs.length; i++) {
var oInput = arrInputs[i];
if (oInput.type == "file") {
var sFileName = oInput.value;
if (sFileName.length > 0) {
var blnValid = false;
for (var j = 0; j < _validFileExtensions.length; j++) {
var sCurExtension = _validFileExtensions[j];
if (sFileName.substr(sFileName.length - sCurExtension.length, sCurExtension.length).toLowerCase() == sCurExtension.toLowerCase()) {
blnValid = true;
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]);
}
break;
}
}
if (!blnValid) {
alert("Sorry, " + sFileName + " is invalid, allowed extensions are: " + _validFileExtensions.join(", "));
return false;
}
}
}
}
return true;
}
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2 answers
I can work it out. Below are the correct codes. :)
JavaScript
<SCRIPT type="text/javascript">
function ValidateFileUpload() {
var fuData = document.getElementById('fileChooser');
var FileUploadPath = fuData.value;
//To check if user upload any file
if (FileUploadPath == '') {
alert("Please upload an image");
} else {
var Extension = FileUploadPath.substring(
FileUploadPath.lastIndexOf('.') + 1).toLowerCase();
//The file uploaded is an image
if (Extension == "gif" || Extension == "png" || Extension == "bmp"
|| Extension == "jpeg" || Extension == "jpg") {
// To Display
if (fuData.files && fuData.files[0]) {
var reader = new FileReader();
reader.onload = function(e) {
$('#blah').attr('src', e.target.result);
}
reader.readAsDataURL(fuData.files[0]);
}
}
//The file upload is NOT an image
else {
alert("Photo only allows file types of GIF, PNG, JPG, JPEG and BMP. ");
}
}
}
</SCRIPT>
Input when it changes:
<input type="file" name="dataFile" id="fileChooser" onchange="return ValidateFileUpload()" />
To display an image before uploading:
<img src="images/noimg.jpg" id="blah">
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We solved it. Here is the complete code :) This code will help you
- Loading and displaying an image (not loading function)
- Image expansion check
- Reset img in case the check returns false
function show(input) {
debugger;
var validExtensions = ['jpg','png','jpeg']; //array of valid extensions
var fileName = input.files[0].name;
var fileNameExt = fileName.substr(fileName.lastIndexOf('.') + 1);
if ($.inArray(fileNameExt, validExtensions) == -1) {
input.type = ''
input.type = 'file'
$('#user_img').attr('src',"");
alert("Only these file types are accepted : "+validExtensions.join(', '));
}
else
{
if (input.files && input.files[0]) {
var filerdr = new FileReader();
filerdr.onload = function (e) {
$('#user_img').attr('src', e.target.result);
}
filerdr.readAsDataURL(input.files[0]);
}
}
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<div class="form-group">
Upload Your Image
<div class="col-md-10">
<div>
<img id="user_img"
height="130"
width="130"
style="border:solid" />
</div>
<div>
<input type="file" title="search image" id="file" name="file" onchange="show(this)" />
</div>
</div>
</div>
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