Is there a way to limit a css to only apply to what is in a content area and not the entire page?

Is there a way to limit a css to only apply to what is in a content area and not the entire page?

I have an ASP.NET 4.0 开发者_运维百科app. I obtained some from someone else that I don't understand (It's javascript and uses a css). By his instructions, I put it on the page to style a list (UL). All of this occurs within a content place holder. However, now some UL's on the MasterPage are also being affected by this style.

Is the content placeholder an html element - if so you can add a class or id to that and use it to limit the css styling for your ul's to only those in the "main" section. If not, you may need to wrap your content in an extra div:

e.g.

<div id="main"> 
<!-- content here including the ul -->
</div>

then the css to style that is:

#main ul
{
// styling here
}

As Kris says, you can use an id selector. This is "The right way" to do it.

If that won't work due to your constraints (running impenetrable mystery code), you may need another option.

Fortunately, the kludge is pretty straightforward too: put the app in an iframe and host it from a separate, blank page.