This input element accepts a filename, which may only be programmatically set to the empty string

Question

I found the following directive to read a file:

.directive('fileSelect', function() {
    var template = '<input type="file" id="files" class="hide"/>';
    return function(scope, elem, attrs) {
        var selector = $(template);
        elem.append(selector);
        selector.bind('change', function(changeEvent) {
            var reader = new FileReader();
            reader.onloadend = function(loadEvent) {
                scope.$apply(function() {
                    if (loadEvent && loadEvent.target && loadEvent.target.result)
                        scope[attrs.fileSelect] = loadEvent.target.result;
                    if (changeEvent && changeEvent.target && changeEvent.target.files && changeEvent.target.files.length > 0)
                        scope[attrs.path] = changeEvent.target.files[0].name;
                });
            };
            if (changeEvent && changeEvent.target &&
                changeEvent.target.files && changeEvent.target.files.length > 0)
                reader.readAsText(changeEvent.target.files[0]);
        });
        scope.$watch(attrs.fileSelect, function(file) {
            selector.val(file);
        });
    };
});

I put in the html the following element:

<div file-select="content" path="url" class="hide"></div>

When I read a file, I got the following exception from the selector.val(file);:

Error: Failed to set the 'value' property on 'HTMLInputElement': This input element accepts a filename, which may only be programmatically set to the empty string.

Can anyone help me?

Answer 1

Ok, first of all here is a working jsFiddle.

Seems like angular didn't like that you change the attribute which is also the directive, the "file-select" attribute.

By taking it out to a different attribute ('content' attribute in my example) we avoid the problem.

In line 15 of the script I changed

scope[attrs.fileSelect] = loadEvent.target.result;

To

scope[attrs.content] = loadEvent.target.result;

You then need to provide the 'content' attribute in the directive call, like this:

<div file-select content="content" path="url" class="hide"></div>

I happen to run into similar problems in the past when trying to save some space in my html, so I just avoid it and prefer declaring these types of directives with element restriction.