function initGridTabs()
{
    for( var tc=0; tc<=7; tc++ )
    {
        // there is no tab #5 which used to be PPV
        if(tc!=5)
        {
            // create the image arrays
            tabsOn[tc] = new Image();
            tabsOff[tc] = new Image();
            tabsHov[tc] = new Image();
            tabsGry[tc] = new Image();
            // load the actual images
            if (tc == 1) {
                tabsOn[tc].src = "/listings/images/gridtab" + tc + "a-on.gif";
                tabsOff[tc].src = "/listings/images/gridtab" + tc + "a-off.gif";
                tabsHov[tc].src = "/listings/images/gridtab" + tc + "a-hov.gif";
                tabsGry[tc].src = "/listings/images/gridtab" + tc + "a-gry.gif";
            }
            else {
                tabsOn[tc].src = "/listings/images/gridtab" + tc + "-on.gif";
                tabsOff[tc].src = "/listings/images/gridtab" + tc + "-off.gif";
                tabsHov[tc].src = "/listings/images/gridtab" + tc + "-hov.gif";
                tabsGry[tc].src = "/listings/images/gridtab" + tc + "-gry.gif";
            }
            // force the image retrieval
            dummy1 = tabsOn[tc].height;
            dummy2 = tabsOff[tc].height;  
            dummy3 = tabsHov[tc].height;  
            dummy4 = tabsGry[tc].height;  
        }
    }
}

function disableNavigation(bTrue)
{
	var obj = document.getElementById("dateSelect");
	if(obj) { obj.disabled = bTrue; }

	obj = document.getElementById("timeSelect");
	if(obj) { obj.disabled = bTrue; }
    
	obj = document.getElementById("btnGoButton");
	if(obj) { obj.disabled = bTrue; }    

	obj = document.getElementById("btnGoButton");
	if (obj) {
		if (bTrue) { obj.style.cursor = "default"; obj.src = "/listings/images/v2/go-gry.gif"; }
		else { obj.style.cursor = "pointer"; obj.src = "/listings/images/v2/go.gif"; } 
	}
}

function disableTabs(bTrue, bIncludeNavigation)
{
	var obj;
	bTabsDisabled = bTrue;
    iCurrentTab = parseInt(optionGenreFilter,10);
 	
    for(var i=0; i<tabsOn.length; i++)
    {
        obj = document.getElementById("gtabimg"+i);
        if(obj)
        {
            if(bTrue)
            {                
                obj.src = tabsGry[i].src;
            }
            else
            {
                // special handling of favs tab
                if((i==1)&&(selectChannels.options.length<=0))
                {
                    obj.src = tabsGry[i].src;
                }
                else
                {
                    if(i==iCurrentTab)
                    {
                        obj.src = tabsOn[i].src;
                    }
                    else
                    {
                        obj.src = tabsOff[i].src;
                    }
                }
            }
        }
    }
    
	obj = null; 
    
    if(bIncludeNavigation)
    {
		disableNavigation(bTrue);
	}
	
    obj = document.getElementById("HdOnlyChk");
    if (obj) { obj.disabled = bTrue; }

    obj = document.getElementById("HdOnlyTextString");
    if (obj) {
        if (bTrue) { obj.style.color = "#AAAAAA";}
        else { obj.style.color = "#000000";}
    }    
}

function clearTabCursors()
{
    for(var i=0; i<tabsOn.length; i++)
    {
        var obj = document.getElementById("gtaba"+i);
        if(obj)
        {
            obj.style.cursor = "default";
        }
    }
}

function tabHiLite(tabid)
{
    tabid = parseInt(tabid,10);

    iCurrentTab = tabid;
    
    var obj = null;
    
    // turn OFF all tabs
    for(var n=0; n<9; n++)
    {
        obj = document.getElementById("gtabimg"+n);
        if(obj)
        {
            // leave favs gray if no favs selected
            if(n==1)
            {
                if(selectChannels.options.length<=0)
                {  
                    obj.src = tabsGry[n].src; 
                    obj.alt = "Click the channel hearts to add favorites to this tab"; 
                    obj.style.cursor = "default";
                }
                else
                {
                    obj.src = tabsOff[n].src; 
                    obj.alt = "Click to display your favorite channels"; 
                    obj.style.cursor = "pointer";
                }
            }
            else 
            { 
                obj.src = tabsOff[n].src; 
            }
            obj.blur();
        }
    }    
     
    // turn ON selected tab   
    obj = document.getElementById("gtabimg"+tabid);
    if(obj)
    {
        obj.src = tabsOn[tabid].src;
        obj.blur();
    }
}

function tabClick(obj, tabid)
{
	// if(bTabsDisabled) { return; }
	if(iSingleSourceID>0){ return; }
	
    tabid = parseInt(tabid,10);

    if((isOptionsVisible())||(tabid==iCurrentTab))
    {
        return;
    }
    
    if((tabid==1)&&(selectChannels.options.length<=0)) 
    {
        return;
    }
    
    // hilite this tab
    tabHiLite(tabid);
    
    // update genre selector       
    objGenreSelect.value = tabid;   
    
    // remove any scrolling
    iGridScrollTop = -1;
    
    var lastTab = iCurrentTab;

    iCurrentTab = parseInt(tabid,10);
    
    // fire genreChange event
    switch(tabid)
    {
        case 0:
            toggleSearch(false);  
			disableNavigation(false);
            if((tabid!=iLastGenreValue)||(optionFavChannels))
            {
                optionFavChannels = false;
                doGenreChange(objGenreSelect);
            }
            break;        
        case 7:
            toggleSearch(true);
			disableNavigation(true);
            break;
        default:        
            toggleSearch(false);  
			disableNavigation(false);                      
            if(tabid!=iLastGenreValue)
            {
                doGenreChange(objGenreSelect);
            }
            break;
    }
    
    // reset the cursor
    if (obj)
    {
		if(obj.style)
		{
			obj.style.cursor = "default";
		}
    }
    
}

function gtabhov(objTD, tabid)
{
    if((isOptionsVisible())||(bTabsDisabled))
    {
        return;
    }

    tabid = parseInt(tabid,10);

    if(tabid==iCurrentTab)
    {
        objTD.style.cursor = "default";
        return;
    }
    
    if((tabid==1)&&(selectChannels.options.length<=0))
    {
        objTD.style.cursor = "default";
        return;
    }

    objTD.style.cursor = "pointer";
     
    var objImg = document.getElementById("gtabimg"+tabid); 
    if(objImg)
    {
        objImg.src = tabsHov[tabid].src; 
    }     
}

function gtaboff(objTD, tabid)
{
    if((isOptionsVisible())||(bTabsDisabled))
    {
        return;
    }
    
    tabid = parseInt(tabid,10);
    
    if((tabid==1)&&(selectChannels.options.length<=0))
    {
        objTD.style.cursor = "default";
        return;
    }
    
    var objImg = document.getElementById("gtabimg"+tabid); 
    if(objImg)
    {
        if(tabid!=iCurrentTab)
        {        
            objImg.src = tabsOff[tabid].src; 
        }
    }
}


// this comment is necessary