var myrules = {		
	'.botao' : function(el){
		el.onmouseover = function(){
			this.className = "botao hover";
		}
		el.onmouseout = function(){
			this.className = "botao";
		}
		el.onfocus = function(){
		    this.className = "botao hover";
		}
		el.onblur = function(){
			this.className = "botao";
		}
	}
};

Behaviour.register(myrules);

function changeImage(v)
{   
    if(v.lastIndexOf("blank.gif")>0)
    {      
        return v;
    }
 

    if(v.indexOf("_hover.",1)>0)
    {   
        v = v.replace(/_hover./,".");
    }
    else
    {
        var x = v.lastIndexOf(".");
        if(x>0)
        {
          var xx = v.substring(0,x);
          var xz = v.substring(x);
          xz = xz.replace(/./,"_hover.");
          v = xx + xz;
        }       
    }   
    return v;
}