JS File Input Restricting

I know there is some way (I am not sure if it is with JavaScript) that you can restrict the files that people can see when they click the browse button on the file input. I am checking it again with PHP when it submits of course but this would make it easier while people are uploading their files. I have looked around but can't find much and don't know the search term to use. I have also tried the HTML accept attribute but that didn't work:
<input type="file" name="file1" id="upload1" accept="image/gif" /> it just showed all files. I can't remember where I have seen this before though so I can't check their code.

 

Use the accept attribute for the input element:

ACCEPT=ContentTypes (media types for file upload)

"Commonly used content types include text/html, image/jpeg, audio/mpeg, video/quicktime, text/css, and text/javascript."

http://htmlhelp.com/reference/html40/values.html#contenttypes

 

I tried it and it didn't work with FireFox, Chrome or IE.

 

you should be doing this on the server side, assume EVERYTHING from client is malicious.

 

I am, I just want to do this so people can find the right images easier and quicker.

 

<form enctype="multipart/form-data">

 

...How would that help?