autoGrow = function($input) {
		var currentWidth = null;
	
		var update = function(e, options) {
			var value, keyCode, printable, placeholder, width;
			var shift, character, selection;
			e = e || window.event || {};
			options = options || {};
	
			if (e.metaKey || e.altKey) return;
			if (!options.force && $input.data('grow') === false) return;
	
			value = $input.val();
			if (e.type && e.type.toLowerCase() === 'keydown') {
				keyCode = e.keyCode;
				printable = (
					(keyCode >= 97 && keyCode <= 122) || // a-z
					(keyCode >= 65 && keyCode <= 90)  || // A-Z
					(keyCode >= 48 && keyCode <= 57)  || // 0-9
					keyCode === 32 // space
				);
	
				if (keyCode === KEY_DELETE || keyCode === KEY_BACKSPACE) {
					selection = getSelection($input[0]);
					if (selection.length) {
						value = value.substring(0, selection.start) + value.substring(selection.start + selection.length);
					} else if (keyCode === KEY_BACKSPACE && selection.start) {
						value = value.substring(0, selection.start - 1) + value.substring(selection.start + 1);
					} else if (keyCode === KEY_DELETE && typeof selection.start !== 'undefined') {
						value = value.substring(0, selection.start) + value.substring(selection.start + 1);
					}
				} else if (printable) {
					shift = e.shiftKey;
					character = String.fromCharCode(e.keyCode);
					if (shift) character = character.toUpperCase();
					else character = character.toLowerCase();
					value += character;
				}
			}
	
			placeholder = $input.attr('placeholder');
			if (!value && placeholder) {
				value = placeholder;
			}
	
			width = measureString(value, $input) + 4;
			if (width !== currentWidth) {
				currentWidth = width;
				$input.width(width);
				$input.triggerHandler('resize');
			}
		};
	
		$input.on('keydown keyup update blur', update);
		update();
	}
Sets up an input to grow horizontally as the user
types. If the value is changed manually, you can
trigger the "update" handler to resize:

$input.trigger('update');

@param {object} $input