In order to provide the user with a different experience for web pages viewed on touch-enabled devices many JavaScript techniques are available on the web. One of the most popular of these is the Modernizr.touch method, which you can see here: http://modernizr.github.com/Modernizr/touch.html.

However, as the list on the Modernizr Touch tests page shows, there is no support for Internet Explorer. In order to test for touch in Internet Explorer 10, which will ship with the first batch of Windows 8 tablets later this year, you can call the window.navigator.msMaxTouchPoints method:

if (window.navigator.msMaxTouchPoints) {
// touch device
}
else {
// non-touch device
}

This method will also return the number of touch-points supported. For example:

if (window.navigator.msMaxTouchPoints >= 2) {
// device supports two or more touch points
}
else if (window.navigator.msMaxTouchPoints) {
// device supports one touch points
}
else {
// non-touch device
}

In order to get touch detection to work across a large cross-section of browsers you could obviously combine this technique with Modernizr. Something like this:

var hasTouch = window.navigator.msMaxTouchPoints || Modernizr.touch;