function Navigation() {
	var BeforeNavFunction = null;

	this.SetBeforeNavFunction = function(func) {
		BeforeNavFunction = func;
	}

	this.GoTo = function(url) {
		if(BeforeNavFunction != null) {
			if(!BeforeNavFunction())
				return;
		}

		location.href = url;
	}
}

var Nav = new Navigation();