Can I trigger a CSS event in mobile safari upon iphone orientation change?

I can't believe no one talked about the css ruling:

@media screen and (max-width: 320px) // Portait Mode
{
/* CSS RULINGS */
p{}
body{}
}

@media screen and (min-width: 321px) // Landscape Mode
{
/* CSS RULINGS */
p{}
body{}
}

You can use the window.orientation property. Its value is the degree that the current mode of view is used. Here is a brief example:

function updateOrientation()
{   
    var orientation=window.orientation;
    switch(orientation)
    {

        case 0:

                break;  

        case 90:
                break;

        case -90:   

                break;
    }

}

You can use this function on this event:

window.onorientationchange=updateOrientation;

Hope that helps!

Best not to set the onorientationchange property directly. Instead use the following:

window.addEventListener('orientationchange', function (evt) {
    switch(window.orientation) {
        case 0: // portrait
        case 180: // portrait
        case 90: // landscape
        case -90: // landscape
    }
}, false);