scrollIntoViewIfNeeded-polyfill.js

/**
 * scrollIntoViewIfNeeded() polyfill
 * by Hubert Sablonnière - https://gist.github.com/hsablonniere/2581101
 */
if (!Element.prototype.scrollIntoViewIfNeeded) {
	Element.prototype.scrollIntoViewIfNeeded = function (centerIfNeeded) {
		centerIfNeeded = arguments.length === 0 ? true : !!centerIfNeeded;

		var parent = this.parentNode,
			parentComputedStyle = window.getComputedStyle(parent, null),
			parentBorderTopWidth = parseInt(parentComputedStyle.getPropertyValue('border-top-width')),
			parentBorderLeftWidth = parseInt(parentComputedStyle.getPropertyValue('border-left-width')),
			overTop = this.offsetTop - parent.offsetTop < parent.scrollTop,
			overBottom = (this.offsetTop - parent.offsetTop + this.clientHeight - parentBorderTopWidth) > (parent.scrollTop + parent.clientHeight),
			overLeft = this.offsetLeft - parent.offsetLeft < parent.scrollLeft,
			overRight = (this.offsetLeft - parent.offsetLeft + this.clientWidth - parentBorderLeftWidth) > (parent.scrollLeft + parent.clientWidth),
			alignWithTop = overTop && !overBottom;

		if ((overTop || overBottom) && centerIfNeeded) {
			parent.scrollTop = this.offsetTop - parent.offsetTop - parent.clientHeight / 2 - parentBorderTopWidth + this.clientHeight / 2;
		}

		if ((overLeft || overRight) && centerIfNeeded) {
			parent.scrollLeft = this.offsetLeft - parent.offsetLeft - parent.clientWidth / 2 - parentBorderLeftWidth + this.clientWidth / 2;
		}

		if ((overTop || overBottom || overLeft || overRight) && !centerIfNeeded) {
			this.scrollIntoView(alignWithTop);
		}
	};
}