Styling a file input field. Works in IE7+ and of course in all other browsers. Additional styling may be needed. Based on quirksmodes article: http://www.quirksmode.org/dom/inputfile.html
No-Library (pure JS), HTML, CSS, JavaScript
Note that 150 of these lines are blank or comments, so it's actually more like 300 lines.
jQuery 1.9.1, HTML, CSS, JavaScript