src/javascript/runtime/html4/file/FileInput.js
function addInput() {
			var comp = this, I = comp.getRuntime(), shimContainer, browseButton, currForm, form, input, uid;

			uid = Basic.guid('uid_');

			shimContainer = I.getShimContainer(); // we get new ref every time to avoid memory leaks in IE

			if (_uid) { // move previous form out of the view
				currForm = Dom.get(_uid + '_form');
				if (currForm) {
					Basic.extend(currForm.style, { top: '100%' });
					// it shouldn't be possible to tab into the hidden element
					currForm.firstChild.setAttribute('tabindex', -1);
				}
			}

			// build form in DOM, since innerHTML version not able to submit file for some reason
			form = document.createElement('form');
			form.setAttribute('id', uid + '_form');
			form.setAttribute('method', 'post');
			form.setAttribute('enctype', 'multipart/form-data');
			form.setAttribute('encoding', 'multipart/form-data');

			Basic.extend(form.style, {
				overflow: 'hidden',
				position: 'absolute',
				top: 0,
				left: 0,
				width: '100%',
				height: '100%'
			});

			input = document.createElement('input');
			input.setAttribute('id', uid);
			input.setAttribute('type', 'file');
			input.setAttribute('accept', _mimes.join(','));

			if (I.can('summon_file_dialog')) {
				input.setAttribute('tabindex', -1);
			}

			Basic.extend(input.style, {
				fontSize: '999px',
				opacity: 0
			});

			form.appendChild(input);
			shimContainer.appendChild(form);

			// prepare file input to be placed underneath the browse_button element
			Basic.extend(input.style, {
				position: 'absolute',
				top: 0,
				left: 0,
				width: '100%',
				height: '100%'
			});

			if (Env.browser === 'IE' && Env.verComp(Env.version, 10, '<')) {
				Basic.extend(input.style, {
					filter : "progid:DXImageTransform.Microsoft.Alpha(opacity=0)"
				});
			}

			input.onchange = function() { // there should be only one handler for this
				var file;

				if (!this.value) {
					return;
				}

				if (this.files) { // check if browser is fresh enough
					file = this.files[0];
				} else {
					file = {
						name: this.value
					};
				}

				file = new File(I.uid, file);

				// clear event handler
				this.onchange = function() {}; 
				addInput.call(comp); 

				comp.files = [file];

				// substitute all ids with file uids (consider file.uid read-only - we cannot do it the other way around)
				input.setAttribute('id', file.uid);
				form.setAttribute('id', file.uid + '_form');
				
				comp.trigger('change');

				input = form = null;
			};


			// route click event to the input
			if (I.can('summon_file_dialog')) {
				browseButton = Dom.get(_options.browse_button);
				Events.removeEvent(browseButton, 'click', comp.uid);
				Events.addEvent(browseButton, 'click', function(e) {
					if (input && !input.disabled) { // for some reason FF (up to 8.0.1 so far) lets to click disabled input[type=file]
						input.click();
					}
					e.preventDefault();
				}, comp.uid);
			}

			_uid = uid;

			shimContainer = currForm = browseButton = null;
		}
function addInput() {
			var comp = this, I = comp.getRuntime(), shimContainer, browseButton, currForm, form, input, uid;

			uid = Basic.guid('uid_');

			shimContainer = I.getShimContainer(); // we get new ref every time to avoid memory leaks in IE

			if (_uid) { // move previous form out of the view
				currForm = Dom.get(_uid + '_form');
				if (currForm) {
					Basic.extend(currForm.style, { top: '100%' });
					// it shouldn't be possible to tab into the hidden element
					currForm.firstChild.setAttribute('tabindex', -1);
				}
			}

			// build form in DOM, since innerHTML version not able to submit file for some reason
			form = document.createElement('form');
			form.setAttribute('id', uid + '_form');
			form.setAttribute('method', 'post');
			form.setAttribute('enctype', 'multipart/form-data');
			form.setAttribute('encoding', 'multipart/form-data');

			Basic.extend(form.style, {
				overflow: 'hidden',
				position: 'absolute',
				top: 0,
				left: 0,
				width: '100%',
				height: '100%'
			});

			input = document.createElement('input');
			input.setAttribute('id', uid);
			input.setAttribute('type', 'file');
			input.setAttribute('accept', _mimes.join(','));

			if (I.can('summon_file_dialog')) {
				input.setAttribute('tabindex', -1);
			}

			Basic.extend(input.style, {
				fontSize: '999px',
				opacity: 0
			});

			form.appendChild(input);
			shimContainer.appendChild(form);

			// prepare file input to be placed underneath the browse_button element
			Basic.extend(input.style, {
				position: 'absolute',
				top: 0,
				left: 0,
				width: '100%',
				height: '100%'
			});

			if (Env.browser === 'IE' && Env.verComp(Env.version, 10, '<')) {
				Basic.extend(input.style, {
					filter : "progid:DXImageTransform.Microsoft.Alpha(opacity=0)"
				});
			}

			input.onchange = function() { // there should be only one handler for this
				var file;

				if (!this.value) {
					return;
				}

				if (this.files) { // check if browser is fresh enough
					file = this.files[0];
				} else {
					file = {
						name: this.value
					};
				}

				file = new File(I.uid, file);

				// clear event handler
				this.onchange = function() {}; 
				addInput.call(comp); 

				comp.files = [file];

				// substitute all ids with file uids (consider file.uid read-only - we cannot do it the other way around)
				input.setAttribute('id', file.uid);
				form.setAttribute('id', file.uid + '_form');
				
				comp.trigger('change');

				input = form = null;
			};


			// route click event to the input
			if (I.can('summon_file_dialog')) {
				browseButton = Dom.get(_options.browse_button);
				Events.removeEvent(browseButton, 'click', comp.uid);
				Events.addEvent(browseButton, 'click', function(e) {
					if (input && !input.disabled) { // for some reason FF (up to 8.0.1 so far) lets to click disabled input[type=file]
						input.click();
					}
					e.preventDefault();
				}, comp.uid);
			}

			_uid = uid;

			shimContainer = currForm = browseButton = null;
		}
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