How should this code be improved? For instance:

  • How could it be shorter, clearer, deal with memory better, use a plugin/library, better prepared for web input?
  • I can break up and clarify the regex or jump calculation, but what is the simplest way?
  • Why don't I see setTimeout cleared in if blocks more or default return values in || inline? Am I dealing with the (potential) values properly?
  • Are there any other typewriter snippets or plugins accessible online that function with HTML5 rules and entities in a clearer way or is there a reason this is not often mentioned?


A typewriter effect outputs human readable characters one by one simulating actual typewriters. To ouput valid HTML5, entities, and text, sometimes we have to first output more than one character (like an entity or tag), and then output the rest of the tags in the block so that the A) outputted HTML snippet is not misread (according to its original state when output into the DOM), and B) so that the HTML in the snippet does not get read by the browser as part of any existing HTML on the page (in the DOM beneath the inserted snippet).




<div id="homepageSnippet"><p>A paragraph in an html5 snippet with no end tag &amp; some text and entities.&#8482;<div><a href="http://www.w3.org/TR/html-markup/p.html#p">W3:paragraph</a></div>

Output, base state:

<div id="showSnippet"></div>

//Output HTML snippet - A char one by one, and a tag or an entity all at once  
//Output all upcoming tags to preserve DOM integrity  
var showSnippet = (function (target, snippet, snippetL, i, interval) {  
    var timeOut = 0,vis = '',tags = '',jump = [];  
    if (i < snippetL) {  
        if (snippet[i] === '<' || snippet[i] === '&') {  
            jump = snippet.substring(i).match(/^<[^>]+>|^&#?[A-Za-z0-9]+(?:;|\s|$|\v|\f|(<))/m);  
            i = i + (jump[0] || '1').length - 1 - (jump[1] || '').length;  
        vis = snippet.substring(0, i + 1) || '';  
        tags = ((snippet.substring(i + 1).match(/(<[^>]+>)/img) || []).join('')) || '';  
        $(target).html(vis + tags);  
        timeOut = window.setTimeout(function () {  
            showSnippet(target, snippet, snippetL, i, interval);  
        }, interval);  
    } else {  

//Get the widget html #pagenameSnippet and call showSnippet  
//with the hardcoded div #showSnippet for output  
var customizeSnippet = (function(page) {  
    var snippet = '', snippetL = 0;  
    snippet = $('div.'+page+'Snippet').html() || '';  
    snippetL = snippet.length;  
    if (snippetL > 0){  
          showSnippet("#showSnippet", snippet, snippetL, 0, 100);  
        }, 100);  
  • \$\begingroup\$ Hi. Welcome to Code Review! Could you explain more about what your code does? If you were asking someone else to write this code, what would you tell that person? What is a typewriter effect? How does it relate to captions? What do you mean when you say that it handles HTML5, entities, and text? Try to work that into a statement of what the problem is that this code solves. It wouldn't hurt to give input, output, and usage examples. \$\endgroup\$ – Brythan Feb 13 '15 at 17:28
  • \$\begingroup\$ @Brythan Thanks. I renamed 'caption' to snippet and added a description and one input example. I can always write out the regex rules and paste a code link if that helps.. \$\endgroup\$ – lette Feb 13 '15 at 18:15

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