How to hide and show left navigation items in CRM 4.0

The first you need to do when you want to manipulate the left navigation section is to create a general function to get a reference to a navigation block. The reason is because each time you want to hide or show a block or nav item you need the DOM reference of the navigation block so instead of copying the code every time, you write a function and you call it everywhere.

Get the DOM reference to a left navigation block in CRM 4.0

/* Jscript: Get the DOM reference */
function GetNavBlock(block)
 {
    var objBlockDetails = document.getElementById("_NA_Info");
    var objBlockSales = document.getElementById("_NA_SFA");
    var objBlockService = document.getElementById("_NA_CS");
    var objBlockMarketing = document.getElementById("_NA_MA");
    var objNavBlock = null;    

    if (objBlockDetails.innerText.substr(0, objBlockDetails.innerText.indexOf(":")).toLowerCase() == block.toLowerCase())
        objNavBlock = objBlockDetails;
    else if (objBlockSales.innerText.substr(0, objBlockSales.innerText.indexOf(":")).toLowerCase() == block.toLowerCase())
        objNavBlock = objBlockSales;
    else if (objBlockService.innerText.substr(0, objBlockService.innerText.indexOf(":")).toLowerCase() == block.toLowerCase())
        objNavBlock = objBlockService;
    else if (objBlockMarketing.innerText.substr(0, objBlockMarketing.innerText.indexOf(":")).toLowerCase() == block.toLowerCase())
        objNavBlock = objBlockMarketing;
    else
        throw "The navigation block '" + block + "' doesn't exists.";

    return objNavBlock;
 }

Hide a navigation block in CRM 4.0

/* Jscript: Hide a navigation block */
 function HideNavBlock(block){
    var objNavBlock = GetNavBlock(block);
    objNavBlock.parentElement.style.display = "none";
 }

Show a navigation block in CRM 4.0

 
/* Jscript: Show a navigation block */
function ShowNavBlock(block){
    var objNavBlock = GetNavBlock(block);
    objNavBlock.parentElement.style.display = "";
}

Hide a navigation item in a navigation block in CRM 4.0

 
/* Jscript: Hide a navigation item in a navigation block */
function HideNavItem(block, item){
    var objNavBlock = GetNavBlock(block);
    for (var i=0; i    {
        var menuItem = objNavBlock.nextSibling.childNodes[i];
        if (menuItem.childNodes[0].childNodes[1].innerText == item)
            menuItem.style.display = "none";
    }
}

Show a navigation item in a navigation block in CRM 4.0

 
/* Jscript: Show a navigation item in a navigation block */
function ShowNavItem(block, item)
{
    var objNavBlock = GetNavBlock(block);

    for (var i=0; i    {
        var menuItem = objNavBlock.nextSibling.childNodes[i];

        if (menuItem.childNodes[0].childNodes[1].innerText == item)
            menuItem.style.display = "";
    }
}