This kind of menus tend to produce large page size, which will have obvious performance impact. For sites with large number of pages (tabs), it's not necessary for the site navigation menu to load all the page links, should take advantage of the hierarchy structure to give viewers just enough links to go around.
Let's count some numbers, in characters:
www.npschools.com, home page,
html total: 196,315
menu: 92,282
ViewSate: 59,664
these two is over 77% of the page total;
DotNetNuke site, home page,
tatol: 115,140
Solpartmenu: 8,784, spmenu.js : 74,892
viewstate: 22,140
27% without counting spmenu.js , 92% of page total with spmenu.js, which will be cached, so just load once.
My site is also a modified IBuySpy, the home page,
total: 14895
menu: 3208
viewstate: 32
menu & viewstate count for 22%, the size of menu & viewstate is generally this size, about 4-6K, no matter what viewable content on the page.
ASP.NET performs a lot better, that is, the server side processing, but care should be still given to what it will produce, so not to overload network with huge Html source.
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