code: function(label, funct, doc)
  	{
  		doc = (doc != null) ? doc : document;
  		
  		var button = doc.createElement('button');
  		mxUtils.write(button, label);
  
  		mxEvent.addListener(button, 'click', function(evt)
  		{
  			funct(evt);
  		});
  		
  		return button;
  	}
docs: Function: button
  
  Returns a new button with the given level and function as an onclick
  event handler.
  
  (code)
  document.body.appendChild(mxUtils.button('Test', function(evt)
  {
  alert('Hello, World!');
  }));
  (end)
  
  Parameters:
  
  label - String that represents the label of the button.
  funct - Function to be called if the button is pressed.
  doc - Optional document to be used for creating the button. Default is the
  current document.