Moodle course files uploader

extra.js

if (window.location.pathname.search('course/view') > 0) {
window.onload = function (event) {
    if (typeof FormData === 'undefined') {
        return;
    }

    var forms = document.forms;

    for (var f = 0; f < forms.length; ++f) {
        if (typeof forms[f].edit !== 'undefined') {
           if (forms[f].edit.value != 0) {
              return;
           }
           var course = {'id': forms[f].id.value, 'sesskey': forms[f].sesskey.value};
           break;
        }
    }

    var sections = document.getElementsByClassName('section main');

    for (var i = 0; i < sections.length; ++i) {
        var section = sections[i];

        section.addEventListener('dragenter', function (event) {
            event.stopPropagation();
            event.preventDefault();
        }, false);

        section.addEventListener('dragover', function (event) {
            event.stopPropagation();
            event.preventDefault();
        }, false);

        section.addEventListener('drop', function (event) {
            event.stopPropagation();
            event.preventDefault();

            var files = event.dataTransfer.files;

            if (!files.length) {
                return;
            }

            var target = event.currentTarget;

            var formData = new FormData();
            formData.append('choose', '');
            formData.append('id', course.id);
            formData.append('sesskey', course.sesskey);
            formData.append('save', 'save');

            formData.append('action', 'makedir');
            formData.append('name', target.id);

            var xhr = new XMLHttpRequest();
            xhr.open('POST', '../files/index.php', false);
            xhr.send(formData);

            formData.append('wdir', '/' + target.id);

            var formRes = new FormData();
            formRes.append('_qf__mod_resource_mod_form', 1);
            formRes.append('cmidnumber', '');
            formRes.append('add', 'resource');
            formRes.append('course', course.id);
            formRes.append('section', target.id.substr(8));
            formRes.append('type', 'file');
            formRes.append('sesskey', course.sesskey);

            for (var j = 0; j < files.length; ++j) {
                var file = files[j];
                formData.append('userfile', file);
                formData.append('action', 'upload');

                var xhr = new XMLHttpRequest();
                xhr.open('POST', '../files/index.php', false);
                xhr.send(formData);

                formRes.append('name', file.name);
                formRes.append('reference[value]', target.id + '/' + file.name);

                var xhr = new XMLHttpRequest();
                xhr.open('POST', '../course/modedit.php', false);
                xhr.send(formRes);
            }
            window.location.reload();
        }, false);
    }
}}