if (!Array.prototype.indexOf)
{
  Array.prototype.indexOf = function(elt, from)
  {
    var len = this.length;

    var from = Number(arguments[1]) || 0;
    from = (from < 0)
         ? Math.ceil(from)
         : Math.floor(from);
    if (from < 0)
      from += len;

    for (; from < len; from++)
    {
      if (from in this &&
          this[from] === elt)
        return from;
    }
    return -1;
  };
}

function add_class_name(element, className)
{
	var currentClassNames = element.className.split(' ');
	
	var classNames = [];
	for(var i = 0; i < currentClassNames.length; ++i)
	{
		if('' == currentClassNames[i]) continue;
		if(classNames.indexOf(currentClassNames[i]) >= 0) continue;
		classNames.push(currentClassNames[i]);
	}
	classNames.push(className);
	element.className = classNames.join(' ');
}
function remove_class_name(element, className)
{
	var currentClassNames = element.className.split(' ');
	
	var classNames = [];
	for(var i = 0; i < currentClassNames.length; ++i)
	{
		if('' == currentClassNames[i]) continue;
		if(classNames.indexOf(currentClassNames[i]) >= 0) continue;
		if(className == currentClassNames[i]) continue;
		classNames.push(currentClassNames[i]);
	}
	element.className = classNames.join(' ');
}