Develop Reference

Adding tooltip with data from csv file to a choropleth map

I'm trying to add a tooltip with data on a choropleth map. It already appears on mouse over but I'm stuck trying to show the data that's in the csv file I used to create the map. I'd like to show the "name" + "pop" + "%".
Here's how I loaded the data:
d3.queue()
.defer(d3.json, "https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/world.geojson")
.defer(d3.csv, "https://raw.githubusercontent.com/lcercos/geojson/main/eurostat_data-map.csv", function(d) { data.set(d.code, +d.pop); })
.await(ready);
Here's the on mouse over function:
function ready(error, topo) {
var div = d3.select("body").append("div") // calling tooltip
.attr("class", "tooltip")
.style("opacity", 0);
let mouseOver = function(d) {
d3.selectAll(".Country")
.transition()
.duration(100)
.style("opacity", .5)
d3.select(this)
.transition()
.duration(100)
.style("opacity", 1)
.style("stroke", "black");
div.transition()
.duration(50)
.style("opacity", 1);
div.html(d.name + d.value + "%") // html data <- Is here the problem?
.style("left", (d3.event.pageX + 15) + "px")
.style("top", (d3.event.pageY - 10) + "px");
}
let mouseLeave = function(d) {
d3.selectAll(".Country")
.transition()
.duration(0)
.style("opacity",)
d3.select(this)
.transition()
.duration(0)
.style("stroke", "transparent");
div.transition()
.duration("50")
.style("opacity", 0);
}

Tooltip not showing up in a chart

I define the tooltip:
var tooltip = d3.select(TARGET_ELEMENT).append("div")
.attr("class", "tooltip")
.style("opacity", 50)
.attr("style", "position: absolute; pointer-events: none; background: lightsteelblue; width:200px; height:28px;");
and then work with it as I have seen in various examples:
g.selectAll("dot")
.data(Dataset)
.enter().append("circle")
.attr("r", 3)
.attr("cx", function(d) { return xScale(d.date); })
.attr("cy", function(d) { return yS(d.value[a]); })
.on("mouseover", function(d) {
tooltip.transition()
.duration(200)
.style("opacity", .9);
tooltip.html(d["date"] + "<br/> (" +"TEST"+ ")")
.style("left", (d3.event.pageX + 5) + "px")
.style("top", (d3.event.pageY - 28) + "px");
})
.on("mouseout", function(d) {
tooltip.transition()
.duration(500)
.style("opacity", 0);
});
However, nothing is showing up. No errors in the console. I verified that the "mouseover" is invoked correctly but that is it. What is the problem with this code?

I assume that you are using d3 v4/v5. Just change the tooltip to:
var tooltip = d3.select("#target").select(".tooltip").data([0]);
tooltip = tooltip.enter().append("div")
.attr("class", "tooltip")
.merge(tooltip)
.style("opacity", 50)
.attr("style", "position: absolute; pointer-events: none; background:lightsteelblue; width:200px;height:28px;")
You can learn about d3 general update patter here.
I've also created a simple fiddle for this.

D3.js How to add tooltip in my legend using line graph

I draw a line graph using D3.js and i am using tooltip in line graph,but i am also using tooltip in legends but enable to show the tooltip in legends,i wrote given code,it is possible to show the tooltip in legends.
var dates=[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31];
var legend = canvas.append("g")
.attr("class", "legend")
// .attr("transform", "translate(70,10)");
var legendRect = legend.selectAll('rect').data(dates);
legendRect.enter()
.append("rect")
.attr("x", function (d,i){return i*14;})
.attr("width", 12)
.attr("height", 20)
.attr("y", 10)
.style("fill","steelblue")
legend.selectAll("text")
.data(dates)
.enter()
.append("text")
.attr("x", function (d,i){return i*14;})
.attr("y", 25)
.attr("font-family", "sans-serif")
.attr("font-size", "11px")
.attr("fill", "white")
.text(function(d) {
return d;
})
.on("mouseover", function(d) {
div.transition()
.duration(200)
.style("opacity", .9);
div .html(formatTime(d.key) + "<br/>" + d.value)
.style("left", (d3.event.pageX) + "px")
.style("top", (d3.event.pageY-28) + "px");
})
.on("mouseout", function(d) {
div.transition()
.duration(500)
.style("opacity", 0);
});
Iam adding tooltip in text but enable to show the tooltip in my values(I have only problem in legend tooltip)

Check out this code. It does exactly what you want.
This is also a great example.

tooltip to show single element of group

I have a bar chart and I have text values at the end of each bar. What I would like to do is set text to invisible, and on mouseover I'd like it to show the number associated with the bar, at the magnitude of that bar. I'm having trouble figuring out how to do this in an efficient manner.
var tooltip = d3.select("body").append("div")
.style("position", "absolute")
.attr("class", "tooltip")
.style("opacity", 0);
var rect = svg.selectAll("rect")
.attr("class", "rect")
.data(dataset)
.enter()
.append("rect")
.attr("y", function(d,i){
return yScale(i);
})
.attr("x", 0)
.attr("width", function(d,i){
return xScale(d);
})
.attr("height", h/dataset.length)
.style("fill", function(d,i){
return colors(d);
})
.on("mouseover", function(d){
d3.select(this).style("opacity", 0.5)
tooltip.transition()
.duration(200)
.style("opacity", 1);
tooltip.html(d)
.style("left", d3.event.pageX + "px")
.style("top", d3.event.pageY + "px")
})
.on("mouseout", function(d){
d3.select(this).style("opacity", 1)
tooltip.transition()
.duration(500)
.style("opacity", 0)
});

Instead of mouseover and mouseout, I recommend doing it with $(this).hover and $(this).mousemove. Try something like this:
$(this).hover(
function() {
tooltip.transition()
.duration(200)
.style("opacity", 1)
// In order to trigger the magnitude or 'width' of the rect:
var rectWidth = $(this).attr("width");
}, function () {
tooltip.transition()
.duration(500)
.style("opacity", 1e-6)
}
);
/*$(this).mousemove(function(event) {
tooltip
.style("left", event.clientX + "px")
.style("top", event.clientY + "px")
});*/

d3.js change color and size on line graph dot on mouseover

I made a line graph with d3.js (see the attached image1).
I managed to insert tooltips on graph dots when mouseover.
I'd like to change color and size of dots too. I tried in many ways but it seems really difficult. Any help?
Here is the piece of code:
svg.selectAll("dot")
.data(data)
.enter().append("circle")
.attr("r", 5.5)
.style("fill", "#fff8ee")
.style("opacity", .8) // set the element opacity
.style("stroke", "#f93") // set the line colour
.style("stroke-width", 3.5)
.attr("cx", function(d) { return x(d.date); })
.attr("cy", function(d) { return y(d.close); })
.on("mouseover", function(d) {
div.transition()
.duration(70)
.style("opacity", .7)
;
div .html(formatTime(d.date) + "<br/>" + d.close)
.style("left", (d3.event.pageX) + "px")
.style("top", (d3.event.pageY - 28) + "px");
})
.on("mouseout", function(d) {
div.transition()
.duration(200)
.style("opacity", 0);
});

Just set color and size in the handlers:
.on("mouseover", function(d) {
d3.select(this).attr("r", 10).style("fill", "red");
})
.on("mouseout", function(d) {
d3.select(this).attr("r", 5.5).style("fill", "#fff8ee");
});

I don't know why, but while d3.select(this) used to work, it doesn't anymore. I now use d3.select(event.currentTarget).
So, if we consider svg as the graph and all its circles being red by default, we can change the color of the circles to green on mouseover and return the color to red on mouseout like this:
svg.on("mouseover", function(d){
d3.select(event.currentTarget)
.style("fill", "green");
})
.on("mouseout", function(d){
d3.select(event.currentTarget)
.style("fill", "red");
});