d3.select()

d3.select(selector)

Selects the first element that matches the specified selector string. If no elements match the selector, returns an empty selection. If multiple elements match the selector, only the first matching element (in document order) will be selected. For example, to select the first anchor element:

var anchor = d3.select("a");

If the selector is not a string, instead selects the specified node; this is useful if you already have a reference to a node, such as this within an event listener or a global such as document.body. For example, to make a clicked paragraph red:

d3.selectAll("p").on("click", function() {
  d3.select(this).style("color", "red");
});