Having issues with ios UIWebView scrolling

I have this function I am running in a UIWebView. It works in Android as window.onscroll = scrollFunc; .. with ios I am doing document.ontouchend = scrollFunc; not sure if this is the right method. (I don't think it is, considering I also need to add an onclick method).

The other problem I am having is that ONLY the scroll up action is being called even though the diffY number comes back as negative when scrolling down and positive when scrolling up. I can't figure out why.

var prevDate = Date.now(); var curDate = prevDate;
                                function scrollFunc(e) {
                                    curDate = Date.now();
                                    if((curDate - prevDate) > 1000){ 
                                        if ( typeof scrollFunc.y == 'undefined' ) {
                                            scrollFunc.y=window.pageYOffset;
                                        }
                                        var diffY=scrollFunc.y-window.pageYOffset;
                                        if( diffY<-3 ) {
                                            // Scroll down action here
                                        } else if( diffY>5 ) {
                                            // Scroll up action here
                                        } else {
                                            // First scroll event
                                        }

                                        scrollFunc.y=window.pageYOffset;
                                        prevDate = curDate;
                                    }
                                }