function escapeHtml(string) {
	  var str = '' + string;
	  var match = matchHtmlRegExp.exec(str);

	  if (!match) {
	    return str;
	  }

	  var escape;
	  var html = '';
	  var index = 0;
	  var lastIndex = 0;

	  for (index = match.index; index < str.length; index++) {
	    switch (str.charCodeAt(index)) {
	      case 34:
	        // "
	        escape = '&quot;';
	        break;
	      case 38:
	        // &
	        escape = '&amp;';
	        break;
	      case 39:
	        // '
	        escape = '&#x27;'; // modified from escape-html; used to be '&#39'
	        break;
	      case 60:
	        // <
	        escape = '&lt;';
	        break;
	      case 62:
	        // >
	        escape = '&gt;';
	        break;
	      default:
	        continue;
	    }

	    if (lastIndex !== index) {
	      html += str.substring(lastIndex, index);
	    }

	    lastIndex = index + 1;
	    html += escape;
	  }

	  return lastIndex !== index ? html + str.substring(lastIndex, index) : html;
	}
Escape special characters in the given string of html.

@param  {string} string The string to escape for inserting into HTML
@return {string}
@public