要实现像jQuery命名空间一样的功能，自己写还是挺麻烦的。
原生的JS也可以实现，只是要保留处理程序的引用(代码来自MDN)：

var body =
        document.querySelector('body'),
    clickTarget = document.getElementById('click-target'),
    mouseOverTarget = document.getElementById('mouse-over-target'),
    toggle = false;

function makeBackgroundYellow() {
    'use strict';

    if (toggle) {
        body.style.backgroundColor = 'white';
    } else {
        body.style.backgroundColor = 'yellow';
    }

    toggle = !toggle;
}

clickTarget.addEventListener('click',
    makeBackgroundYellow,
    false
);

mouseOverTarget.addEventListener('mouseover', function () {
    'use strict';

    clickTarget.removeEventListener('click',
        makeBackgroundYellow,
        false
    );
});