Some time we need to rearrange left navigation item of left navigation bar, we can do this easily using JS “insertBefore()” function. Just we need to get element id of the left navigation items. We can use IE dev toolbar to do this; also if you are using IE 8 then IE dev toolbar will not work, as Microsoft has provided inbuilt developer tools in IE 8 (Tools->Developer Tools).

For e.g if we want to insert  “Relationships” navigation item before “Contact” navigation item in Details navigation bar in account form.

Just paste this code on onload event of Account form

var _ContactsNavItem = document.getElementById(“navContacts”).parentNode;

var _RelationshipNavItem = document.getElementById(“navRelationships”).parentNode;

_RelationshipNavItem.insertBefore(_ContactsNavItem);

And you will get result like below

Hope it will help somebody !!!