To limit the types of files that users are allowed to upload, enter a list of accepted extensions (separated by spaces). If the uploaded file name does not end with one of the extensions listed, a 'File Type Invalid' error will be shown to the respondent and the file will not be saved. For instance, to limit the upload to common web graphics, you might enter:

.jpg .gif .png

Please keep in mind that no actual examination of the file is done to determine what type it is, and therefore a respondent could upload a file of the wrong type simply by changing the filename (this is unlikely, but possible). You should always run a virus checker on any files you download from your respondents and never run any program unless you know the person who submitted and trust them.

All space-separated strings will be matched against the end of the filename, ignoring the case of the characters. Therefore, if you enter .jpg, it would also match a file that ends in .JPG.