Disable Menu Buttons from any entity in CRM

Some time user is not interested to show some buttons from menu items, for this user required to hide these buttons. You can do this if you have ID of that button, but in CRM the ID of these buttons not standard these are created at the time of loading, but some part of the ID is unique every time, so find this unique id name from source control of entity.After this use following JavaScript to Hide these buttons.

function DisableButtons()
{
//Get all of the List Elements
var lis = document.getElementsByTagName('LI');
var i = 0;
//Loop through the list items
while (i < lis.length)
{
if (lis[i].getAttribute('id').indexOf( 'provide unique id name')!=-1)
{
var lnkmenuApproveDiscount = lis[i].getAttribute('id');
var menuApproveDiscountButton = document.getElementById(lnkmenuApproveDiscount);
menuApproveDiscountButton.style.display='none';
}
if (lis[i].getAttribute('id').indexOf( 'provide unique id name')!=-1)
{
var lnkmenuRejectDiscount = lis[i].getAttribute('id');
var menuRejectDiscountButton = document.getElementById(lnkmenuRejectDiscount);
menuRejectDiscountButton.style.display='none';
}
i = i + 1;
}
}