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Input Type File and files sizes

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Input Type File and files sizes

Postby marcha » Fri Apr 06, 2007 11:13 am


Is there a working draft speaking about a functionality
that can solve the folowing problem.

when posting a form with attached files (one or more input type file)
there is no way to know the total post request content-length
before submiting the form, this causes server error when the
post size limit is exceeded.

thanks for your help,
Posts: 1
Joined: Fri Apr 06, 2007 11:08 am
Location: Switzerland

Re: Input Type File and files sizes

Postby zcorpan » Wed Sep 19, 2012 3:14 pm

Yes, you can use the .files IDL attribute on the <input> element to get a list of File objects, on which you can read the .size IDL attribute to get the size of each file. (Each <input> can have multiple files if you specify the multiple="" attribute.) ... nput-files ... t-multiple

If you don't use the multiple="" attribute, it's just a matter of getting the first file in the list and using the form validation API:
Code: Select all
var MAX_SIZE = 10 * 1024 * 1024;
function validateFileSize(input) {
  input.setCustomValidity(input.files[0].size > MAX_SIZE ? 'File is larger than '+(MAX_SIZE/1024/1024)+' MB.' : '');
<form enctype=multipart/form-data>
<p><label>Select a file: <input name=file type=file onchange="validateFileSize(this)"></label>
<p><input type=submit value="Send">

If you want to support legacy browsers that don't support setCustomValidity you would need to feature-check for it and fall back to showing a custom message and preventing the form to be submitted the traditional way.

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Joined: Tue Feb 06, 2007 8:29 pm
Location: Sweden

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