d3.js学习2

子选择器，在特定范围内选择元素

<section id="section1">
	<div><h3>div1</h3></div>
</section>
<section id="section2">
	<div><h3>div2</h3></div>
</section>
<script type="text/javascript">
	d3.select("#section1 > div")
	.style("border","2px solid blue");

	d3.select("#section2")
	.select("div")
	.style("border","2px solid red");
</script>

后代连接符 div span

子连接符 div > span 必须是严格的父子关系

函数级联调用（仅使用d3生成页面）

<script type="text/javascript">
	var body = d3.select("body");
	body.append("section")
	.attr("id","section1")
	.append("div")
	    .style("border","2px solid blue")
	.append("p")
	    .text("be my valentine");

	body.append("section")
	.attr("id","section2")
	.append("div")
	    .style("border","2px solid red")
	.append("p")
	    .text("be my darling");
</script>