not getting getWebRelativeFriendlyUrl using sp.publishing.js. Same for getAllParentTerms

I am not getting getWebRelativeFriendlyUrl using sp.publishing.js. Same for getAllParentTerms.

Code below:

function getURL() 
{ // Create an instance of the current context to return context information clientContext = SP.ClientContext.get_current(); 
this.website = clientContext.get_web(); 
var navterm = new SP.Publishing.Navigation.NavigationTerm();
 clientContext.load(navterm) 
//Executes the current pending request asynchronously on the server clientContext.executeQueryAsync(onRequestSucceeded, onRequestFailed); }
 //the delegate of the method that is called when the request is executed successfully function onRequestSucceeded() 
{ 
alert(navterm.getWebRelativeFriendlyUrl());
 alert(navterm.getAllParentTerms()); 
} 
//the delegate of the method that is called when the request is executed unsuccessfully function onRequestFailed(sender, args) 
{ 
alert('Error: ' + args.get_message()); 
} 

I am getting error on

var navterm = new SP.Publishing.Navigation.NavigationTerm();

Please help. Thanks in advance.