Center an element horizontally and/or vertically using JavaScript.

center-element.js

function resize($el) {
    const data = $el.data('center');
    if (data.x) {
        const w_width = $(window).width();
        const e_width = $el.width();
        const margin = (w_width - e_width) / 2;
        $el.css('left', margin)
    }
    if (data.y) {
        const w_height = $(window).height();
        const e_height = $el.height();
        const margin = (w_height - e_height) / 2;
        $el.css('top', margin)
    }
}

$('[data-center]').each(function () {
    const $this = $(this).css('position', 'absolute');
    $(document).ready(() => resize($this));
    $(window).on('resize', () => resize($this))
});

// Use it like <img ... data-center='{"x": true, "y": true}'>