jquery-on-patterns.js

$(document).on('mouseenter', function (event) { /* ... */ });

$(document).on('mouseenter focus', function (event) { /* ... */ });

$(document).on('mouseenter', '.foo', function (event) { /* ... */ });

$(document).on('mouseenter', '.foo, .bar', function (event) { /* ... */ });

$(document).on({
    mouseenter: function (event) { /* ... */ },
    mouseleave: function (event) { /* ... */ }
});

$(document).on({
    'mouseenter focus': function (event) { /* ... */ },
    'mouseleave blur': function (event) { /* ... */ }
});

$(document).on({
    mouseenter: function (event) { /* ... */ },
    mouseleave: function (event) { /* ... */ }
}, '.foo');