I'm using JavaScript to validate an uploading form, one of the conditions is to check if any file has been selected. I thought this would be simple, but I can't get it to work. Is this code invalid? The var file works with other conditions so it's not that
var file = document.getElementById('file');
if(file.value =="") {
alert("no file selected")
return false;
}
<input name="uploaded" type="file" id="file" />
You can use the following example:
var fileInput = document.getElementById('file');
fileInput.onchange = function () {
var input = this.files[0];
if (input) {
//process input.
} else {
alert("Please select a file.");
}
};
Hope this helps.
Related
How to not open the file upload box when input mytextField is null.
<input type="text" id="mytextField">
<input type="file" multiple id="myFileUpload">
<script>
document.getElementById("myFileUpload").addEventListener("click", function () {
var myTextF = document.getElementById("mytextField");
if(myTextF = null || myTextF == ''){
//will not open the file upload
} else {
//let the file upload open
}
});
</script>
You can disable the upload button when textarea is empty and enable it when textarea contains text.
<input type="text" onkeyup="checkField()" id="mytextField">
<input type="file" multiple id="myFileUpload" disabled="disabled">
script:
function checkField(){
var myTextF = document.getElementById("mytextField");
if(myTextF.value.trim() != ""){
document.getElementById("myFileUpload").disabled = false;
}
}
Used the trim() function to prevent empty whitespace texts.
Here you are assigning myTextF to the element, rather than the innerText.
Try with var myTextF = document.getElementById("myTextF").innerText;
If something doesn't work, you could always try to log the output to the console.
In this case, because you are assigning the element, that resolves as TRUE, and it will always try to open the file.
document.getElementById("myFileUpload").addEventListener("click", function () {
var myTextF = document.getElementById("mytextField");
if(myTextF = null || myTextF == ''){
//will not open the file upload
console.log("I should not open file")
} else {
//let the file upload open
console.log("I should open the file")
}
});
" I should open the file"
I'm working on a project and I need the user to upload only pdf files.
I'm trying to do this in the front-end so whenever the input detects a file type that is not a pdf should reject it. Everything seems correct. However, when I hover over the input it shows me that the wrong file is uploaded. So what should I do?
function changeName(elem) {
$("input[type='file']").
elem.on("change", function() {
var fileName = elem.val().split("\\").pop();
var fileExtension = elem.val().split(".").pop();
if (fileExtension === "pdf") {
elem.siblings(".Syllabus").text(fileName);
} else {
elem.siblings(".Syllabus").val('');
elem.siblings(".Syllabus").text('...');
alert('Only PDF files are accepted');
}
});
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<label class="Syllabus fileReset">...</label>
<input type="file" accept="application/pdf" name="file1" onClick="changeName($(this));" required class="upload-button removable" />
This code works better than what you posted
$("input[type='file']").on("change", function(e) {
var elem = $(this);
elem.siblings(".Syllabus").text("...")
var fileName = elem.val().split("\\").pop();
var fileExtension = elem.val().split(".").pop();
if (fileExtension !== "pdf") {
elem.siblings(".Syllabus").text('Only PDF files are accepted')
elem.replaceWith(elem.val('').clone(true));
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<label class="Syllabus fileReset">...</label>
<input type="file" accept="application/pdf" name="file1" required class="upload-button removable" />
I am trying to get the filepath of the selected file.
Using the debugger, I see that the file has an property called value which is equal to : "C:\fakepath\filename.txt".
However when I try to access file.value, the filepath is equal to null.I am using Java 8, Struts 1.2, Jsps, and Chrome
Javascript:
function validateFile(file)
{
filepath = file.value; /*This is null*/
return true;
}
Html:
<input type="file" id="theFile[0]" onChange="validateFile(this)"/>
Try this:
function validateFile(fileinput) {
var allowed = "pdf,png";
var filepath=fileinput.value;
var ext = filepath.substr(filepath.lastIndexOf('.')+1);
if (filepath = "" || allowed.search(ext) <= -1) {
fileinput.value='';
alert('Invalid file type');
return false;
}
}
<input type="file" id="inputFile" onChange="validateFile(this)"/>
I guess it wasn't too much work after all :)
function validateFile(file)
{
filepath = file.value;
document.getElementById('result').innerText = filepath;
return true;
}
<input type="file" onChange="validateFile(this)"/>
<div id="result">[result will be here]</div>
So I am trying to validate file uploading before the file itself is uploaded and would like to check for two conditions - whether or not the file is smaller than 5mb and whether or not the file is in an image format.
This is how I am doing it at the moment:
<script>
$(document).ready(function () {
$('input[type=file]').change(function () {
var fileSize = this.files[0].size/1024/1024;
if (fileSize > 5) { alert("Please check the size of your image");
$(this).val('');
}
var val = $(this).val().toLowerCase();
var regex = new RegExp("(.*?)\.(png|jpg|jpeg|gif)$");
if(!(regex.test(val))) {
$(this).val('');
alert('Only image files are supported. Please check the format of your file and try again.');
}
});
});
</script>
It works fine except that if the file is too big and it is removed, the alert for wrong file type fires too because the input has changed.
Is there any better way to get around this? I'd like to check both conditions without the user getting warned about file format if only the image size is wrong. Could I kill the second function if the first one is triggered?
Here is what you can do, create and manage an array of errors, and use it at the end. Click run to see the demo
$(document).ready(function() {
$('input[type=file]').change(function() {
var file = this.files[0],
val = $(this).val().trim().toLowerCase();
if (!file || $(this).val() === "") { return; }
var fileSize = file.size / 1024 / 1024,
regex = new RegExp("(.*?)\.(png|jpg|jpeg|gif)$"),
errors = [];
if (fileSize > 5) {
errors.push("Please check the size of your image");
}
if (!(regex.test(val))) {
errors.push('Only image files are supported. Please check the format of your file and try again.');
}
if (errors.length > 0) {
$(this).val('');
alert(errors.join('\r\n'));
}
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="file" />
JSP:
----
<div ID="items">
input id="file5" type="file" path="files" name="files" size="40" /> Other documents
</div>
Javascript:
-----------
<script type="text/javascript">
var items=1;
function AddItem() {
var div=document.getElementById("items");
var button=document.getElementById("add");
items++;
newitem="";
newitem+="<input type=\"file\" path=\"files\" name=\"files\"";// + items;
newitem+="\"id=file"+items;
newitem+="\" size=\"40\"> Other documents";
newitem+=" <input type=\"button\" class=\"button\" id=\"delButton"+items;
newitem+="\" value=\"\" name=\"button"+items;
newitem+="\" onclick=deletethisRow("+items+")>";
newnode=document.createElement("div");
newnode.setAttribute("id","child"+items);
newnode.innerHTML=newitem;
div.insertBefore(newnode,button);
}
function deletethisRow(obj){
var fileElement=document.getElementById("file"+obj);
var buttonElement=document.getElementById("delButton"+obj);
var childDivName="child"+obj;
if (buttonElement) {
var child = document.getElementById(childDivName);
var parent = document.getElementById("items");
parent.removeChild(child);
}
}
</script>
---
Above is the JSP code as well as JavaScript snippets.. I'm trying to validate the input files....
I want to allow only jpg,png,pdf,doc,docx file types to be upload??
Any thoughts on how to achieve this?
Thanks and regards,
Satish Krishnamurthy
You can change your input tag:
<input type="file" name="pic" id="pic" accept=".someext, image/gif, image/jpeg" />
But please don't rely on client-side validation. Check it server-side or people can disable the client-side checks and upload even executable scripts.
function Checkfilesextension()
{
var fileToupload = document.getElementById('elementId');
var fileName = fileToupload .value;
var ext = fileName.substring(fileName.lastIndexOf('.') + 1);
ext.toLowerCase
if(ext =="GIF" || other extension) // add other extensions
{
return true;
}
else
{
alert("Upload only the allowed files");
return false;
}
}
This would check for the extension of the files....have not tested the code though