var selected_bot="";
var selected_slide="";

function randomSlideInizialize(){
var random=(1+Math.floor(Math.random()*4));
selected_bot="s_bot"+random;
selected_slide="s_cell"+random;
obj=document.getElementById(selected_bot);
var file=obj.src.split(".png");
obj.src=file[0]+"_c.png";

slide=document.getElementById(selected_slide);
slide.style.display='block';

}

function clickOnSlide(img){
var file=img.src.split(".png");
img.src=file[0]+"_c.png";
obj=document.getElementById(selected_bot);
var file_old=obj.src.split("_c.png");
obj.src=file_old[0]+".png";
selected_bot=img.id;

var spit=img.id.split("s_bot");
var id=spit[1];

slide_old=document.getElementById(selected_slide);
slide_old.style.display='none';

slide=document.getElementById("s_cell"+id);
slide.style.display='block';

selected_slide="s_cell"+id;

}