d3.js——饼状图的拖拽

常规定义：

var width = 500,
    height = 500;
var dataset = [30,10,43,55,13]
var color = d3.scale.category10()
var svg = d3.select("body").append("svg")
    .attr("width",width)
    .attr("height",height)
var pie =d3.layout.pie()var width = 500,
    height = 500;
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