function to_home(){
var curr_div = document.getElementById("contact_div");
curr_div.style.visibility = "hidden";
var div = document.getElementById("home_div");
div.style.visibility = "visible";
return true;
}
function to_contact(){
var curr_div = document.getElementById("home_div");
curr_div.style.visibility = "hidden";
var div = document.getElementById("contact_div");
div.style.visibility = "visible";
return true;
}