var navMenuHideTimer = 0;
var navActiveMenus = [false, true, true, true, false, false, false];

var navImgDir = "images/master/buttons/button_";
var navImgBaseNames = ["home", "tradeservices", "sales", "logistics", "aboutus", "faq", "contactus"];
var navImgSuffix = ".png";

// Returns whether or not the dropdown menu at the 
// given position is listed as active.
function isActiveMenu(menuNo) {
    return navActiveMenus[menuNo];
}

function navOver(imgElement, imgNo) {
    imgElement.src = navImgDir + navImgBaseNames[imgNo] + "_over" + navImgSuffix;
}

function navOut(imgElement, imgNo) {
    imgElement.src = navImgDir + navImgBaseNames[imgNo] + navImgSuffix;
}

function navStartHidingMenus() {
    navMenuHideTimer = setTimeout("navHideAllMenus()", 1000);
}

function navStopHidingMenus() {
    clearTimeout(navMenuHideTimer);
}

function navDropShow(menuNo) {
    navHideAllMenus();
    if (isActiveMenu(menuNo)) {
        document.getElementById("dropDown_" + menuNo).style.display = "block";
    }
}

function navHideAllMenus() {
    var i = 0;
    while (i < 7) {
        navDropHide(i);
        i++;
    }
}

function navUnderlineText(targetId) {
    document.getElementById(targetId).style.textDecoration = "underline";
}

function navRemoveTextUnderline(targetId) {
    document.getElementById(targetId).style.textDecoration = "none";
}

function navDropHide(menuNo) {
    navStopHidingMenus();
    document.getElementById("dropDown_" + menuNo).style.display = "none";
}