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Last active January 13, 2022 23:01
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Linking HTML input and d3.js
license: mit

This is a simple example of implimenting an HTML input using a <range> input tag and using that to adjust a d3.js drawn svg element (a circle).

It is used as an example and described in the book D3 Tips and Tricks.

<!DOCTYPE html>
<meta charset="utf-8">
<title>Input test (circle)</title>
<p>
<label for="nRadius"
style="display: inline-block; width: 240px; text-align: right">
radius = <span id="nRadius-value">…</span>
</label>
<input type="range" min="1" max="150" id="nRadius">
</p>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.17/d3.min.js"></script>
<script>
var width = 600;
var height = 300;
var holder = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);
// draw the circle
holder.append("circle")
.attr("cx", 300)
.attr("cy", 150)
.style("fill", "none")
.style("stroke", "blue")
.attr("r", 120);
// when the input range changes update the circle
d3.select("#nRadius").on("input", function() {
update(+this.value);
});
// Initial starting radius of the circle
update(120);
// update the elements
function update(nRadius) {
// adjust the text on the range slider
d3.select("#nRadius-value").text(nRadius);
d3.select("#nRadius").property("value", nRadius);
// update the rircle radius
holder.selectAll("circle")
.attr("r", nRadius);
}
</script>
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