How to use nify javascript to make round corner box? Im using but not working

How to make round corners with Nifty technique. I included niftycube.js and then called the function Nifty("div.firstblock");. But its not working. Whether i have to include any other JavaScript or CSS??. Help

From stackoverflow

• You need to include the niftyCorners.css as well.

• Please stop, it's not worth your time. Firefox, Safari, Chrome and Konqueror all support their own form of the CSS3 style, border-radius, so put this in your CSS and be done with it:

  .myDiv {
      -moz-border-radius: 5px;
      -webkit-border-radius: 5px;
      -khtml-border-radius: 5px;
      border-radius: 5px;
  }
  

  Giving your divs rounded corners is just a visual nicety and one that can be saved for people with modern browsers. If IE users don't get a rounded border, so what?

  masato-san : Thanks for this, I was getting really mad cuz nifty never worked for me and border-radius works like a charm!