Tooltips doesn't work on d3js - d3.js

Question

I have a problem... I am not able to include tooltips.. i've tried to do it with d3noobs tutorial and with much other.. But it doesn't work..
I hope anyone can help me or fullfill the code!
Thanks a lot!
<pre>
<!-- /.row -->
<div class="row">
<div class="col-lg-12">
<div class="panel panel-default">
<div class="panel-body" id="gr1">
<svg id="graph" viewBox="0 0 100% 100%" preserveAspectRatio="xMidYMid" width="1500" height="600" ></svg>
<script src="http://d3js.org/d3.v3.min.js"></script>
<div id="tooltip" class="hidden" style="left: 429px, top: 489.6px">
<p><strong><span id="city">Dar es Salaam</span></strong></p>
<p id="population">Population: 4 million</p>
</div>
<script>
var margin = {top: 20, right: 20, bottom: 30, left: 40},
width = 1300 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var x0 = d3.scale.ordinal()
.rangeRoundBands([0, width], .1);
var x1 = d3.scale.ordinal();
var y = d3.scale.linear()
.range([height, 0]);
var color = d3.scale.ordinal()
.range(["#FF4000", "#D7DF01", "#DF013A", "#fbf10d"]);
var xAxis = d3.svg.axis()
.scale(x0)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.tickFormat(d3.format(".2s"));
var svg = d3.select("#graph")
.append ("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
function make_x_axis() {
return d3.svg.axis()
.scale(x)
.orient("bottom")
.ticks(5)
}
function make_y_axis() {
return d3.svg.axis()
.scale(y)
.orient("left")
.ticks(20)
}
function mouseover(d) {
d3.select(this).style("fill", "orange");
var mousecoord = [0,0];
mousecoord = d3.mouse(this);
d3.select("#tooltip")
.style("left", mousecoord[0] + "px")
.style("top", mousecoord[1]-75 + "px");
d3.select("#city")
.text(d.city);
d3.select("#population")
.text(function () { return year + " population: " + comma(d["y"+year]); });
d3.select("#tooltip").classed("hidden", false);
};
d3.csv("groupeddatafordefaultdashboard.asp?3", function(error, data) {
var ageNames = d3.keys(data[0]).filter(function(key) { return key !== "State"; });
data.forEach(function(d) {
d.ages = ageNames.map(function(name) { return {name: name, value: +d[name]}; });
});
x0.domain(data.map(function(d) { return d.State; }));
x1.domain(ageNames).rangeRoundBands([0, x0.rangeBand()]);
y.domain([0, d3.max(data, function(d) { return d3.max(d.ages, function(d) { return d.value; }); })]);
svg.append("g")
.attr("class", "grid")
.call(make_y_axis()
.tickSize(-width, 0, 0)
.tickFormat("")
)
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Anzahl");
svg.selectAll("circle")
.data(data)
.enter()
.append("circle")
(blah blah)
.on("mouseover", mouseover)
.on("mouseout", mouseout);
var state = svg.selectAll(".state")
.data(data)
.enter().append("g")
.attr("class", "g")
.attr("transform", function(d) { return "translate(" + x0(d.State) + ",0)"; });
state.selectAll("rect")
.data(function(d) { return d.ages; })
.enter().append("rect")
.attr("width", x1.rangeBand())
.attr("x", function(d) { return x1(d.name); })
.attr("y", function(d) { return y(d.value); })
.attr("height", function(d) { return height - y(d.value); })
.style("fill", function(d) { return color(d.name); });
var legend = svg.selectAll(".legend")
.data(ageNames.slice().reverse())
.enter().append("g")
.attr("class", "legend")
.attr("transform", function(d, i) { return "translate(20," + i * 50 + ")"; });
legend.append("rect")
.attr("x", width - 18)
.attr("width", 18)
.attr("height", 18)
.style("fill", color);
legend.append("text")
.attr("x", width - 24)
.attr("y", 9)
.attr("dy", ".35em")
.style("text-anchor", "end")
.text(function(d) { return d; });
});
</script>
</pre>