From the course: Validating and Processing Forms with JavaScript and PHP

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Limiting uploads by MIME types

Limiting uploads by MIME types

Some HCMO Five attributes are super useful for file validation. You can tell a browser to accept only certain files by using the accept attribute and passing it some MIME types. So what is a MIME type? MIME stands for Multipurpose Internet Mail Extensions. It started out as a format for allowing email attachments in the SNTP protocol, but it has grown way beyond that and is used heavily all over the web. And MIME specification starts out with a main type like image or video, followed by a sub type like JPG or PNG. The accept attribute normally prevents a browser from choosing files that don't meet our criteria. So let's see how that works. Here's a form that's asking the user to upload a file. So I'm going to hit this choose file button. Here I have a bunch of files with different types. So notice that I can choose any of the types that I want. I'm going to hit cancel, and I'll go into the code for this page, and in the file input type, I'm going to add an except attribute. I'll ask…

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