javascript - TypeError cannot set property 'size of' undefined - Stack Overflow

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Trying to get the size of a file when the user uploads file. When user clicks on the browse button to upload file, but instead clicks the cancel button. The filesize type throws an error of undefined.

I tried to use typeof to test condition of filesize is undefined but it does not work. Need help to catch error.

$('#fileupload-image').change(function() {
    $('#select_file').hide();
    $('#upload_image_button').slideDown('fast');
    var filename = $(this).val();

    if(typeof this.files[0].size == 'undefined')
    {
        this.files[0].size = '';
    }
    else 
    {
        var filesize = this.files[0].size;
    }

Trying to get the size of a file when the user uploads file. When user clicks on the browse button to upload file, but instead clicks the cancel button. The filesize type throws an error of undefined.

I tried to use typeof to test condition of filesize is undefined but it does not work. Need help to catch error.

$('#fileupload-image').change(function() {
    $('#select_file').hide();
    $('#upload_image_button').slideDown('fast');
    var filename = $(this).val();

    if(typeof this.files[0].size == 'undefined')
    {
        this.files[0].size = '';
    }
    else 
    {
        var filesize = this.files[0].size;
    }

• javascript
• jquery
• file
• file-upload
• undefined

Share Improve this question Follow edited Dec 16, 2015 at 21:16 TbWill4321 8,68633 gold badges2929 silver badges2525 bronze badges asked Dec 16, 2015 at 21:15 Errol WallaceErrol Wallace 16722 silver badges1313 bronze badges

Add a ment  | 

3 Answers 3

Sorted by: Reset to default 3

another possibility:

var filesize = (this.files.length && this.files[0].size) || '';

First of all, I don't think you actually want to be setting this.files[0].size = '';.

Here's one possibility, using a try/catch to forget all about type checking:

var filesize = '';
try {
    filesize = this.files[0].size;
}
catch {}

Use a this.files.length > 0 check instead of checking to see if it is undefined. Also, if you're checking to see if it's undefined you wouldn't want to be using single quotes either.

本文标签： javascriptTypeError cannot set property 39size of39 undefinedStack Overflow