function StringBuffer()    
	{    
	    this._strings = [];    
	    if(arguments.length==1)    
	    {    
	        this._strings.push(arguments[0]);    
	    }    
	}    
	   
	StringBuffer.prototype.append = function(str)    
	{    
	    this._strings.push(str);    
	    return this;    
	}    
	   
	StringBuffer.prototype.toString = function()    
	{    
	    return this._strings.join("");    
	}