If you want to use the SharePoint 2010 client object model you can use the code below:
ExecuteOrDelayUntilScriptLoaded(getWebUserData, “sp.js“);
var context = null;
var web = null;
var currentUser = null;
function getWebUserData() {
context = new SP.ClientContext.get_current();
web = context.get_web();
currentUser = web.get_currentUser();
currentUser.retrieve();
context.load(web);
context.executeQueryAsync(Function.createDelegate(this, this.onSuccessMethod),
Function.createDelegate(this, this.onFailureMethod));
}
function onSuccessMethod(sender, args) {
var userObject = web.get_currentUser();
var UserTitle = userObject.get_title();
alert(UserTitle);
}
function onFailureMethod(sender, args) {
alert(‘request failed ‘);
}
Here is a video and a simple way to test it.
Image may be NSFW.
Clik here to view.

Clik here to view.
