Can I some pages/website functionality running on jQuery and some on Yui? Can we have both these libraries on one website. Is there a way to use these both libraries on same website.
My question would be why do you want to? Though honestly, YUI is the only thing I piss on harder than jQuery -- since it's mix of being a HTML, CSS and JS framework results in some of the worst websites from an accessibility standpoint there is. Getting web development advice from Yahoo is like getting automotive construction advice from British-Leyland.
It is really never a good idea to have two different libraries on your site. You should pick one and stick with it. Having two libraries can cause a lot of code bloat and negatively effect your load times for end users.
Technically, if each library properly "namespaces" its functions (and the namespaces don't clash), doesn't declare any global functions, and don't override/augment any native object prototypes, they could live together. In reality, however, there is very likely to be a clash (for instance, many libraries define their own $() function). Find the library that best fits your needs and use that one.
yes you can use as many as u like but i try to avoid most of javascript when it comes to IM due to accessibility