Simple jQuery/Zepto plugin for typing character by character texts

letterbyletter.js

/**
 * jQuery.letterByLetter
 * Version 0.3.0
 * 
 * Simple jQuery/Zepto plugin for typing character by character texts 
 * Standard call:

	$('.myDivs').LetterByLetter({
		'speed' : 150
	});

 * Where myDivs is the class of the items you want to type in order of appearance.
 *
 * Available options with defaults

	'speed'     : 150,   // Interval between characters in milliseconds 
	'callback'  : null,  // callback function
	'pause'     : 300    // Delay between texts in milliseconds

 * github.com/jacoborus
 * MIT license
 * 
 */


(function($) {
	'use strict';
	$.fn.LetterByLetter = function(options) {

		var nlayers, alllayers, pos, settings, typing;

		settings = $.extend({
			speed: 150, // Interval between charactersin milliseconds
			callback : null, // Callback function
			pause : 1000 // Delay between texts in milliseconds
		}, options);

		alllayers = this;
		nlayers = this.length;
		pos = 0;

		// hide target layers
		$(this).each(function(index) {
			return $(this).css("display", "none");
		});

		// typing function writes text character by character
		typing = function(capa) {

			var count, step, clock, out, textlong, texto;
			// get the target text
			texto = $(capa).html();
			// get the text long
			textlong = texto.length;
			// out text
			out = "";
			// character counter
			count = 0;

			// write next character
			step = function() {

				// add new character to out and count
				out = out + texto.charAt(count++);
				// write type
				$(capa).html(out);

				// display the layer if first character
				if (count === 1) $(capa).css("display", "");

				// if last character  and type next layer
				if (count === textlong) {
					// stop clock
					window.clearInterval(clock);
					// if not last layer
					if (pos < nlayers) {
						// run next text with delay
						return setTimeout( function(){
							typing($(alllayers)[pos++]);
						}, settings.pause);

					} else {
						// run callback
						if (settings.callback !== null) {
							return settings.callback();
						}
					}
				}
			};

			// avoid repeating first layer
			if (pos === 0) pos++;

			// typing a character every settings.speed milliseconds
			return (clock = setInterval(step, settings.speed));
		};

		// start typing first layer
		typing(this[0]);
	};
})(jQuery);