bookmarklet for latex formula wrapped with [;...;], \[...\], $$...$$, $...$

tex.js

javascript:(function(){
  var R = /\[;.+?;\]|\\\[.+?\\\]|\$\$.+?\$\$|\$.+?\$|./g;
  /* var R = /\[;.+?;\]|\\\[.+?\\\]|\$\$.+?\$\$|./g; */
  
  var spanClick = function(){
    this.nextElementSibling.style.display = 'inline';
    this.style.display = 'none'
  };
  
  var imgClick = function() {
    this.previousElementSibling.style.display = 'inline';
    this.style.display = 'none'
  };
  
  var split = function(text) {
    var arr = text.replace(/\r?\n/, ' ').match(R);
    if (!arr) return;
    var changed = false;
    var res = [];
    var tmpText = '';
    for (var i = 0; i < arr.length; i++) {
      var s = arr[i];
      if (s.length == 1) {
        tmpText += s
      } else {
        if (s[0] === '$' && (s[1] !== '$' || s[s.length - 2] !== '$'))
          s = s.slice(1, s.length - 1);
        else
          s = s.slice(2, s.length - 2);
        changed = true;
        if (tmpText) {
          res.push(document.createTextNode(tmpText));
          tmpText = ''
        }
        
        var span = document.createElement('span');
        span.style.display = 'none';
        span.onclick = spanClick;
        span.innerHTML = s;
        res.push(span);
        var img = document.createElement('img');
        img.src = "http://latex.codecogs.com/gif.latex?" + s;
        img.title = "click to show source";
        img.onclick = imgClick;
        res.push(img)
      }
    }
    if (changed) {
      if (tmpText) {
        res.push(document.createTextNode(tmpText))
      }
      return res
    }
  };

  var traverse = function(node) {
    if (!node) return;
    if (node.nodeType == 3) {
      if (!/^\s*$/.test(node.nodeValue)) {
        var parent = node.parentNode;
        if (!parent) return;
        var newNodes = split(node.textContent);
        if (newNodes) {
          for(var i = 0; i < newNodes.length; i++){
            parent.insertBefore(newNodes[i], node);
          };
          parent.removeChild(node)
        }
      }
    } else if (! /^script|style|link|img|input|textarea|select$/i.test(node.nodeName)) {
      /* pre contains \n that can't be ignored */
      if (/^pre$/i.test(node.nodeName)) {
        node.innerHTML = node.innerHTML.replace(/\r?\n/g, '<br>')
      }
      for (var i = 0, len = node.childNodes.length; i < len; ++i) {
        traverse(node.childNodes[i])
      }
    }
  };
  
  traverse(document.getElementsByTagName('body')[0])
})()