Hiding Left Navigation Groups and Toolbar icon

Hiding icon from MS Dynamics CRM toolbar.

HidePaperClip = function() {
var toolBarButtons = document.all.mnuBar1.rows[0].cells[0].childNodes[0].childNodes;
var btnTitle = "Attach a File";
//Loop through each button
for (var i = 0; i < toolBarButtons.length; i++) {
var button = toolBarButtons[i];
if (button.title.match(btnTitle) != null) {
button.nextSibling.style.display = "none";
button.style.display = "none";
}
}
}

Hiding nvaigation group from MS Dynamics CRM's left navigation panel.

HideSubNav = function() {
var nav = document.all.crmNavBar.childNodes;
var count = 0;
for (var i = 0; i < nav.length; i++) {
var li = nav[i];
if (li.className == "ms-crm-Nav-Group") {
if (count!=0) li.style.display = "none";
count++;
}
}
}