Possible Duplicate:
How can you determine the file size in JavaScript?
GMail has the option to check file size and alerting without letting the page posting back.
How can I implement this feature myself?
Using HTML5, you can achieve this on the client side using JavaScript. This is jQuery but it works without as well of course: http://jsfiddle.net/pimvdb/S4mEv/2/. Note that it's not available in all browsers (yet).
$('#file').change(function() {
alert(this.files[0].size + " bytes");
});
https://developer.mozilla.org/en/DOM/File
You can use Uploadify, it's a jQuery plugin that uses flash for checking file size and has other neat functions. http://www.uploadify.com/documentation/options/sizelimit/
You can do that file HTML5 JS File API
You can test run the below codes in my web IDE (but please use google chrome or FF): http://codesocialist.com/#/?s=bN
The below codes retrieve the filetype and filesize for you :)
<input type="file" id="files" name="files[]" multiple />
<output id="list"></output>
// Check for the various File API support.
if (window.File && window.FileReader && window.FileList && window.Blob) {
// Great success! All the File APIs are supported.
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
// files is a FileList of File objects. List some properties.
var output = [];
for (var i = 0, f; f = files[i]; i++) {
output.push('<li><strong>', escape(f.name), '</strong> (', f.type || 'n/a', ') - ', f.size, ' bytes </strong></li>');
}
document.getElementById('list').innerHTML = '<ul>' + output.join('') + '</ul>';
}
// Bind Event Listener
document.getElementById('files').addEventListener('change', handleFileSelect, false);
} else {
alert('The File APIs are not fully supported in this browser.');
}
Gmail uses a Flash application for this purpose. If you want to check file sizes, you need to do this from within such an environment; JavaScript alone has no mechanism to accomplish this.
