Fragments are placed on top of another instead of replacing

[jas017]

In the demo application,you've written a method changeFragment() for changing the fragments on side menu item click.There,the fragments are not replaced.Instead new fragment is placed above the old one.I am having Webviews in the side menu item clicks in my application.So,i have one Webview where there are youtube videos.So,when i play any video and click on another side menu item,the new page is getting placed on top of old one and the youtube video keeps on playing.Please help me fix this.