var pn_initialized = false; /* Is necessary variables initialized? */
var pn_visibleindex = 0; /* Index in rotateelems (declared below) of the current visible element */

/* The following variables should be assigned proper values in a function named initVariables() */
var pn_rotateelems = null; /* The elements that should be rotated */
var pn_visibledisplay = ""; /* display value for elements in visible state */


/* Initialize variables for rotation */
function pn_initVariables(){
    var rootelem = document.getElementById("tabvideos");
		if (rootelem) {
    var divelems = rootelem.getElementsByTagName("div");
    pn_rotateelems = [];
    for(var i=0; i<divelems.length; i++){
        var current = divelems[i]
            if (current.className.substring(7,0) == "article"){
            pn_rotateelems.push(divelems[i])
        }
    }
		}
    pn_visibledisplay = "block";
}

/* Hide rotatable elements except the current/first */
function pn_hideElems(pn_rotateelems, pn_visibleindex){
    for(i=0; i<pn_rotateelems.length; i++){
        if (i != pn_visibleindex){
            pn_rotateelems[i].style.display = "none";
        }
    }
}

/* call this once at beginning of rotation to initialize variables and hide non-visible elements */
function pn_initialize(){
  pn_initVariables();
	if (pn_rotateelems) {
		pn_hideElems(pn_rotateelems, pn_visibleindex);
		pn_deactivate_prev();
		pn_initialized = true;
	}
}


function pn_nextVideo() {
    /* Make sure init function has been called before proceeding */
    if (!pn_initialized){
        pn_initialize();
    }
    var current = pn_rotateelems[pn_visibleindex];
    if (pn_visibleindex >= pn_rotateelems.length-1){
        pn_visibleindex = pn_rotateelems.length-1;
    }
    else{
        pn_visibleindex += 1;
    }
    if (pn_visibleindex == pn_rotateelems.length-1){
        pn_deactivate_next();
    }
    var next = pn_rotateelems[pn_visibleindex];
    current.style.display = "none";
    try{
      next.style.display = pn_visibledisplay; 
    } catch(e) {
      /* Some browsers (IE) do not understand all possible display values. Empty string works fairly well then. */
      next.style.display = "";
    }
    pn_activate_prev();
}

function pn_prevVideo() {
    /* Make sure init function has been called before proceeding */
    if (!pn_initialized){
        pn_initialize();
    }
    current = pn_rotateelems[pn_visibleindex];
    if (pn_visibleindex < 1){
        pn_visibleindex = 0;
    }
    else{
        pn_visibleindex -= 1;
    }
    if (pn_visibleindex == 0){
        pn_deactivate_prev();
    }
    var prev = pn_rotateelems[pn_visibleindex];
    current.style.display = "none";
    try{
      prev.style.display = pn_visibledisplay; 
    } catch(e) {
      /* Some browsers (IE) do not understand all possible display values. Empty string works fairly well then. */
      prev.style.display = "";
    }
    pn_activate_next();
}

function pn_deactivate_prev(){
    var imgelem = document.getElementById("tabvideoprevlink");
    imgelem.src = "/getfile.php/819096.623.qtyvddryrr/play-prev-inactive.gif";
}

function pn_deactivate_next(){
    var imgelem = document.getElementById("tabvideonextlink");
    imgelem.src = "/getfile.php/819095.623.qxryecfutf/play-next-inactive.gif";
}
function pn_activate_prev(){
    var imgelem = document.getElementById("tabvideoprevlink");
    imgelem.src = "/getfile.php/819094.623.ausdteepep/play-prev.gif";

}

function pn_activate_next(){
    var imgelem = document.getElementById("tabvideonextlink");
    imgelem.src = "/getfile.php/806170.623.xrfsasrbus/play-next.gif";
}