Updated Java Scripts

Hi Community,

i am trying with updated java scripts

i want to get the user name with below code

function test(executionContext)
{
var GlobalContext= executionContext.getGlobalContext();
var name = Xrm.Utility.GlobalContext.userSettings.userName();
alert(name);
}

But, i am not able to get the username and got the error like

TypeError: executionContext.getGlobalContext is not a function at test 

Thanks in Advance