missing ) in parenthetical

I keep getting that my javascript is missing ) in parenthetical [Break On This Error] if ( (this.scrollTop < this.scrollH...uches[0].pageY > scrollStartPosY+5) )

function touchScroll(id){
    if(isTouchDevice()){ //if touch events exist...
        var el=document.getElementById(id);
        var scrollStartPosY=0;
        var scrollStartPosX=0;

        document.getElementById(id).addEventListener("touchstart", function(event) {
            scrollStartPosY=this.scrollTop+event.touches[0].pageY;
            scrollStartPosX=this.scrollLeft+event.touches[0].pageX;
            //event.preventDefault(); // Keep this remarked so you can click on buttons and links in the div
        },false);

        document.getElementById(id).addEventListener("touchmove", function(event) {
            // These if statements allow the full page to scroll (not just the div) if they are
            // at the top of the div scroll or the bottom of the div scroll
            // The -5 and +5 below are in case they are trying to scroll the page sideways
            // but their finger moves a few pixels down or up.  The event.preventDefault() function
            // will not be called in that case so that the whole page can scroll.
            if ( (this.scrollTop < this.scrollHeight-this.offsetHeight) && (this.scrollTop+event.touches[0].pageY < scrollStartPosY-5) || (this.scrollTop != 0 && this.scrollTop+event.touches[0].pageY > scrollStartPosY+5) )
                    event.preventDefault(); 
            if ((this.scrollLeft < this.scrollWidth-this.offsetWidth && this.scrollLeft+event.touches[0].pageX < scrollStartPosX-5) || (this.scrollLeft != 0 && this.scrollLeft+event.touches[0].pageX > scrollStartPosX+5))
                    event.preventDefault(); 
            this.scrollTop=scrollStartPosY-event.touches[0].pageY;
            this.scrollLeft=scrollStartPosX-event.touches[0].pageX;
        },false);
    }
}

And I cannot for the life of me figure out why.

Answer

Try JS Lint. It’s great for finding non-obvious syntax errors on scripts.