This is a polyfill for implementing the HTML5 <input type="number"> element in browsers that do not currently support it.
Using it is easy — simply include the number-polyfill.js file in the HEAD of the HTML page. You can then use <input type="number"> elements normally.
If Modernizr detects that the browser doesn’t support <input type="number">, the script will search for these elements and attach some Javascript to them to make them function as number-only input fields, and add increment/decrement buttons.
A default CSS file is provided. You may edit this file to style the buttons to make them look the way you want.