HTML Upload Max_File_Size Does Not Appear to Work

HTML Upload MAX_FILE_SIZE does not appear to work

MAX_FILE_SIZE is in KB not bytes. You were right, it is in bytes. So, for a limit of 4MB convert 4MB in bytes {1024 * (1024 * 4)} try:

<input type="hidden" name="MAX_FILE_SIZE" value="4194304" /> 

Update 1

As explained by others, you will never get a warning for this. It's there just to impose a soft limit on server side.

Update 2

To answer your sub-question. Yes, there is a difference, you NEVER trust the user input. If you want to always impose a limit, you always must check its size. Don't trust what MAX_FILE_SIZE does, because it can be changed by a user. So, yes, you should check to make sure it's always up to or above the size you want it to be.

The difference is that if you have imposed a MAX_FILE_SIZE of 2MB and the user tries to upload a 4MB file, once they reach roughly the first 2MB of upload, the transfer will terminate and the PHP will stop accepting more data for that file. It will report the error on the files array.

PHP Uploading file unsuccessful

Your Input file is

<input name="uploadedfile" type="file" />

so change $_FILES['fileToUpload']['name'] to $_FILES['uploadedfile']['name']

$_FILES['uploadedfile']['name'] Must have the value of Name attribute of your file field

problem when uploading file

File Uploads - Common Pitfalls

The MAX_FILE_SIZE item cannot specify
a file size greater than the file size
that has been set in the
upload_max_filesize in the php.ini
file. The default is 2 megabytes.

If a memory limit is enabled, a larger
memory_limit may be needed. Make sure
you set memory_limit large enough.

...

If post_max_size is set too small,
large files cannot be uploaded. Make
sure you set post_max_size large
enough.

You can increase the value for MAX_FILE_SIZE three four ways:

1) php.ini

upload_max_filesize = 20M
post_max_size = 20M

2) ini_set()

ini_set('upload_max_filesize', 20M);
ini_set('post_max_size', 20M);

3) .htaccess

php_value upload_max_filesize 20M
php_value post_max_size 20M

4) hidden form fields

<input name="MAX_FILE_SIZE" value="20971520" type="hidden">

Limit the size of a file upload (html input element)

This is completely possible. Use Javascript.

I use jQuery to select the input element. I have it set up with an onChange event.

$("#aFile_upload").on("change", function (e) {

    var count=1;
    var files = e.currentTarget.files; // puts all files into an array

    // call them as such; files[0].size will get you the file size of the 0th file
    for (var x in files) {
    
        var filesize = ((files[x].size/1024)/1024).toFixed(4); // MB
    
        if (files[x].name != "item" && typeof files[x].name != "undefined" && filesize <= 10) { 

            if (count > 1) {
                
                approvedHTML += ", "+files[x].name;
            }
            else {
            
                approvedHTML += files[x].name;
            }

            count++;
        }
    }
    $("#approvedFiles").val(approvedHTML);

});

The code above saves all the file names that I deem worthy of persisting to the submission page before the submission actually happens. I add the "approved" files to an input element's val using jQuery so a form submit will send the names of the files I want to save. All the files will be submitted, however, now on the server-side, we do have to filter these out. I haven't written any code for that yet but use your imagination. I assume one can accomplish this by a for loop and matching the names sent over from the input field and matching them to the $_FILES (PHP Superglobal, sorry I don't know ruby file variable) variable.

My point is you can do checks for files before submission. I do this and then output it to the user before he/she submits the form, to let them know what they are uploading to my site. Anything that doesn't meet the criteria does not get displayed back to the user and therefore they should know, that the files that are too large won't be saved. This should work on all browsers because I'm not using the FormData object.

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