[removed] Capture mouse wheel event and do not scr

问题:

I'm trying to prevent a mousewheel event captured by an element of the page to cause scrolling.

I expected false as last parameter to have the expected result, but using the mouse wheel over this "canvas" element still causes scrolling:

this.canvas.addEventListener('mousewheel', function(event) {
   mouseController.wheel(event);
}, false);

Outside of this "canvas" element, the scroll needs to happen. Inside, it must only trigger the .wheel() method. What am I doing wrong?

回答1:

You can do so by returning false at the end of your handler.

this.canvas.addEventListener('wheel',function(event){
    mouseController.wheel(event);
    return false; 
}, false);

Updated to use the wheel event as mousewheel deprecated for modern browser as pointed out in comments.

The question was about preventing scrolling not providing the right event so please check your browser support requirements to select the right event for your needs.

回答2:

Have you tried event.preventDefault()?

this.canvas.addEventListener('mousewheel',function(event){
    mouseController.wheel(event);
    event.preventDefault();
}, false);

回答3:

Just adding, I know that canvas is only HTML5 so this is not needed, but just in case someone wants crossbrowser/oldbrowser compatibility, use this:

/* To attach the event: */
addEvent(el, ev, func) {
    if (el.addEventListener) {
        el.addEventListener(ev, func, false);
    } else if (el.attachEvent) {
        el.attachEvent("on" + ev, func);
    } else {
        el["on"+ev] = func; // Note that this line does not stack events. You must write you own stacker if you don't want overwrite the last event added of the same type. Btw, if you are going to have only one function for each event this is perfectly fine.
    }
}

/* To prevent the event: */
addEvent(this.canvas, "mousewheel", function(event) {
    if (!event) event = window.event;
    event.returnValue = false;
    if (event.preventDefault)event.preventDefault();
    return false;
});

回答4:

This kind of cancellation seems to be ignored in newer Chrome >18 Browsers (and perhaps other WebKit based Browsers). To exclusively capture the event you must directly change the onmousewheel method of the element.

this.canvas.onmousewheel = function(ev){
    //perform your own Event dispatching here
    return false;
};