gistfile1.js

// Rough method to determining a file's type based upon it's extension.
// Requires jQuery
function getFileType(filename) {
    // Get the extension of the file
    var extension = filename.split('.').pop().toLowerCase();

    // File types and their corresponding possible extensions.
    var types = {
        'image': ['jpg', 'jpeg', 'gif', 'png', 'bmp'],
        'audio': ['wav', 'mp3', 'wma'],
        'text': ['doc', 'docx', 'txt'],
        'pdf': ['pdf'],
        'powerpoint': ['ppt', 'pptx'],
        'excel': ['xls', 'xlsx']
    };
    
    for (t in types) {
        // Check to see if the extension is a member of each key's array... if so, return the key.
        if ($.inArray(extension, types[t]) >= 0) { return t; }
    }
}