var _slide_num = 2;
var _timer = setTimeout ( "changeSlider(_slide_num,false)", 7000);
function clickChangeSlider(which,clicked){
    changeSlider(which,clicked);
    clearTimeout ( _timer );
}

function changeSlider(which,clicked){
   
    resetSlides();
    document.getElementById("slide_" + which).style.display = "";
    document.getElementById("slide_num_"+ which).className= "slide_number slide_active_number";
    
    if(!clicked){
       if(_slide_num < 3)
         _slide_num +=1;
       else 
         _slide_num = 1;
    
       _timer = setTimeout ( "changeSlider(_slide_num)", 7000);
    }
}

function resetSlides(){
    document.getElementById("slide_1").style.display = "none";
    document.getElementById("slide_2").style.display = "none";
    document.getElementById("slide_3").style.display = "none";

    document.getElementById("slide_num_1").className= "slide_number";
    document.getElementById("slide_num_2").className= "slide_number";
    document.getElementById("slide_num_3").className= "slide_number";
}