Why does a fixed background-image move when scrolling on IE?

Question

I\'m trying to make background-image fixed.

As you see in my blog, the background-image is moving when scrolling on IE 11.

How can

Answer 1

Here is a way to handle PageUP and PageDOWN keyS based on the previous answers :

if(navigator.userAgent.match(/Trident\/7\./)) { // if IE
    $('body').on("mousewheel", function () {
        // remove default behavior
        event.preventDefault(); 

        //scroll without smoothing
        var wheelDelta = event.wheelDelta;
        var currentScrollPosition = window.pageYOffset;
        window.scrollTo(0, currentScrollPosition - wheelDelta);
    });
    $('body').keydown(function (e) {
        var currentScrollPosition = window.pageYOffset;

        switch (e.which) {
            case 33: // page up
                e.preventDefault(); // prevent the default action (scroll / move caret)
                window.scrollTo(0, currentScrollPosition - 600);
                break;
            case 34: // page down
                e.preventDefault(); // prevent the default action (scroll / move caret)
                window.scrollTo(0, currentScrollPosition + 600);
                break;
            case 38: // up
                e.preventDefault(); // prevent the default action (scroll / move caret)
                window.scrollTo(0, currentScrollPosition - 120);
                break;
            case 40: // down
                e.preventDefault(); // prevent the default action (scroll / move caret)
                window.scrollTo(0, currentScrollPosition + 120);
                break;
            default: return; // exit this handler for other keys
        } 
    });

}