Adapts textarea rows to content length (opposed to a fixed height based approach) IE8+

textarea-dynamic-rows.js

(function() {
	
	/* resize textarea based on text content (with IE8 support & no fixed heights or pseudo-divs!) */
	
	// jquery
	var textarea = $('textarea');
	if(textarea.length) textarea.on('input propertychange', function() {
		this.rows = ((this.value || '').match(/(\r?\n)/mg) || []).length + 1;
	}).trigger('input');
	
	// vanilla 
	var textarea = document.querySelectorAll('textarea'),
	legacy = !('addEventListener' in window);
	if(textarea.length) for(var i = 0; i < textarea.length; i++) {
		textarea[i][legacy ? 'attachEvent' : 'addEventListener'].apply(textarea[i],
			[legacy ? 'onpropertychange' : 'input', (function() {
				var fnc = function(e) {
					if(!e && legacy) e = window.event; var el = ('id' in this ? this : (e.target || e.srcElement));
					el.rows = ((el.value || '').match(/(\r?\n)/mg) || []).length + 1;
				}; fnc.apply(textarea[i], []);

				return fnc;
			})(), false]
		);
	}
		
})();