window.setInterval timer doesent work... on an iphone!

window.setInterval timer doesent work... on an iphone!

Hi.

I´ve created a simple page, and a jquery script with a timer function that adds some text to a div:

window.setInterval(testfunction, 5000);

function testfunction() {
    $('#DynamicDiv').append(" apended some text!);
}

This works fine in IE, Firefox and safari.
But on my iphone, the function is not being executed. Other Jquery stuff works fine, but this timer doesent. Any idea why, and is there a fix?

Thanks alot for your help :)

kind regards
Lars